Dr Alejandro Trejo Baños

@article{hen2023,

title = {First principles study of hydrogen storage on B-doped SiC monolayers 2 through light transition metal atoms},

author = {F. De Santiago and L. G. Arellano and I. J. Hern\'{a}ndez-Hern\'{a}ndez and A. R. Heredia and \'{A}. Miranda and A. Trejo and Luis A. P\'{e}rez and Miguel Cruz-},

year  = {2023},

date = {2023-09-13},

urldate = {2023-09-13},

journal = {International Journal of Hydrogen Energy},

volume = {En revisi\'{o}n},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{energystore2023b,

title = {DFT insights into Cu-driven tuning of chemisorption and physisorption in the hydrogen storage by SnC monolayers},

author = {R. Bermeo-Campos and L. G. Arellano and \'{A}. Miranda and F. Salazar and A. Trejo and R. Oviedo-Roa and M. Cruz-Irisson},

year  = {2023},

date = {2023-09-13},

urldate = {2023-09-13},

journal = {Journal of Energy Storage},

volume = {En revisi\'{o}n},

keywords = {2D monolayers, Density functional calculations},

pubstate = {published},

tppubtype = {article}

}

@article{Jim\'{e}nez-S\'{a}nchez_Morales-Vergara_Salazar_Miranda_Trejo_Hern\'{a}ndez-Hern\'{a}ndez_P\'{e}rez_Cruz-Irisson_2023,

title = {Theoretical study of [111]-germanium nanowires as anode materials in rechargeable batteries: a density functional theory approach},

author = {Ricardo Jim\'{e}nez-S\'{a}nchez and Pedro Morales-Vergara and Fernando Salazar and Alvaro Miranda and Alejandro Trejo and Ivonne J. Hern\'{a}ndez-Hern\'{a}ndez and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://rmf.smf.mx/ojs/index.php/rmf/article/view/6816},

doi = {10.31349/RevMexFis.69.031604},

year  = {2023},

date = {2023-05-01},

urldate = {2023-05-01},

journal = {Revista Mexicana de F\'{i}sica},

volume = {69},

number = {3 May-Jun},

pages = {031604 1\textendash},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Thirumuruganandham2023,

title = {Ab Initio Calculations of Chitosan Effects on the Electronic Properties of Unpassivated Triangular ZnO Nanowires Oriented along [0001] Directions},

author = {Saravana Prakash Thirumuruganandham and Jos\'{e} Luis Cuevas Figueroa and Alejandro Trejo Ba\~{n}os and Duncan John Mowbray and Thibault Terencio and Miguel Ojeda Martinez},

url = {https://doi.org/10.1021/acsomega.2c06740},

doi = {10.1021/acsomega.2c06740},

year  = {2023},

date = {2023-01-17},

journal = {ACS Omega},

volume = {8},

number = {2},

pages = {2337-2343},

publisher = {American Chemical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZ2023106840,

title = {Exploring the electronic and mechanical properties of lithium-decorated silicon carbide nanowires for energy storage},

author = {Mario Gonzalez and Fernando Salazar and Alejandro Trejo and \'{A}lvaro Miranda and Roc\'{i}o Nava and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S2352152X23002372},

doi = {https://doi.org/10.1016/j.est.2023.106840},

issn = {2352-152X},

year  = {2023},

date = {2023-01-01},

journal = {Journal of Energy Storage},

volume = {62},

pages = {106840},

abstract = {The high chemical stability of silicon carbide (SiC) is attractive to inhibit unwanted side chemical reaction and prolongate the cyclability performance of lithium ion batteries anodes. However, SiC has high surface lithiation energy barrier due to its intrinsic nature and the low electrical conductivity limited the application in this area. The surface modification of SiC is an alternative to boost the lithiation\textendashdelithiation kinetics. Hydrogen incorporation on SiC surface is extensively used in semiconductor industry to passivate electrically active centers. In this work, we present a theoretical study of the effect of surface lithium (Li) atoms on the electronic and mechanical properties of hydrogen passivated SiC nanowires (H-SiCNWs) with zinc-blende structure. The results show that the adsorption of Li on the carbon (C) atoms at the surface of the nanowire introduces new electronic states within the former band gap of the H-SiCNWs, whose main contribution comes from the C and silicon (Si) atoms in the valence and conduction bands, respectively. Moreover, the number of new bands within the former band gap increases as a function of the concentration of Li atoms and the systems remain as intrinsic semiconductors up to the maximum Li concentrations. The formation energy reveals that the stability of the nanowires increases when the concentration of Li atoms augments. Moreover, the values of the open circuit voltage are found between 1.6 and 1.9 V for all studied concentrations of Li atoms and morphologies. The charge population analysis indicates that the Li atoms give up charge to the C ones resulting in ionic bonds. On the other hand, the Young modulus of the H-SiCNWs increases when their diameter augments and their values are lower than that of the bulk SiC. Besides, the Young modulus slightly diminishes when the concentration of Li grows, then the mechanical resistance could offer a large useful life of the electrode. Finally, the maximum theoretical storage capacity values indicate that the SiC nanowires (SiCNWs) are good potential anodic materials for rechargeable Li-ion batteries.},

keywords = {Anodes, Density Functional Theory, Lithium ion batteries, SiC nanowires},

pubstate = {published},

tppubtype = {article}

}

@article{JIMENEZSANCHEZ2023102745,

title = {Surface Li effects on the electronic properties of GaAs nanowires: A first principles approach},

author = {Ricardo Jim\'{e}nez-S\'{a}nchez and Sara E. P\'{e}rez-Figueroa and Alejandro Trejo-Ba\~{n}os and \'{A}lvaro Miranda and Fernando Salazar and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S2468023023001153},

doi = {https://doi.org/10.1016/j.surfin.2023.102745},

issn = {2468-0230},

year  = {2023},

date = {2023-01-01},

journal = {Surfaces and Interfaces},

volume = {38},

pages = {102745},

abstract = {The quest for the improvement of Li-Ion batteries has directed attention towards semiconductor nanostructures, like nanowires. However, the surface interactions and effects of Li on the electronic properties of these nanostcrutures has been less explored. Especially the possible modifications to the properties of GaAs nanowires that arise from having Li on its surface have been seldom studied. In this work, we employed Density Functional Theory to study the effects of surface Li on the electronic properties of H passivated GaAs nanowires grown along the [111] direction. To determinate the isolated effects of Li on either surface Ga or As, only Li bonded to either Ga[GaAsNW_Ga-Li] or As[GaAsNW_As-Li] were considered, and up to 6 Li were placed on the respective nanowire surfaces. The results indicate that the energy gap is a function of the Li concentration, the nanowire diameter and the placement of Li on the nanowire surface. The binding energy is independent of the number of Li on the nanowire surface, where the GaAsNW_Ga-Li has slower binding energies compared to the GaAsNW_As-Li, but the binding energies and band gaps in both cases are high, which would hinder the application of these nanowires in Li ion batteries.},

keywords = {DFT, GaAs nanowires, Surface passivation},

pubstate = {published},

tppubtype = {article}

}

@article{SANTANA2023102584,

title = {Highly sensitive amphetamine drug detection based on silicon nanowires: Theoretical investigation},

author = {Jos\'{e} Eduardo Santana and Akari Narayama Sosa and Francisco De Santiago and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Alejandro Trejo and Fernando Salazar and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S2468023022008392},

doi = {https://doi.org/10.1016/j.surfin.2022.102584},

issn = {2468-0230},

year  = {2023},

date = {2023-01-01},

journal = {Surfaces and Interfaces},

volume = {36},

pages = {102584},

abstract = {Amphetamine (AA) is used in some therapeutic treatments, but it is also one of the most widely used illicit drugs. Therefore, a correct tracking of AA in various environments is crucial for its controlled distribution even inside the human body. However, current sensors are still too large to fit inside the human body and their biocompatibility is still deficient. Since the discovery of nanostructures, especially silicon nanowires (SiNWs), the possibilities of sensors inside the human body have increased due to their enhanced properties and biocompatibility. However, theoretical studies about the capabilities of SiNWs with surface modifications as sensing materials are still scarce. Using Density Functional Theory, we investigate the effects of amphetamine adsorption on the work function, and other electronic and structural properties, of pristine and modified SiNWs. Two types of modifications were studied, i.e., substitutional doping with B, Al, and Ga atoms and surface functionalization with the same species. The adsorption energies of the amphetamine molecule are larger for the doped nanowires, followed by the functionalized ones, and lastly, the undoped Si nanowire.This study shows that undoped, doped, and functionalized SiNWs are excellent candidates for AA sensing, with B being the best chemical species for improving AA adsorption for both doped and functionalized schemes.},

keywords = {Amphetamine, DFT, Doping, Drug, Sensor, Silicon nanowires},

pubstate = {published},

tppubtype = {article}

}

@article{BERMEOCAMPOS2023157481,

title = {Surface morphology effects on the mechanical and electronic properties of halogenated porous 3C-SiC: A DFT study},

author = {R. Bermeo-Campos and K. Madrigal-Carrillo and S. E. Perez-Figueroa and M. Calvino and A. Trejo and F. Salazar and A. Miranda and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0169433223011595},

doi = {https://doi.org/10.1016/j.apsusc.2023.157481},

issn = {0169-4332},

year  = {2023},

date = {2023-01-01},

journal = {Applied Surface Science},

volume = {631},

pages = {157481},

abstract = {Silicon carbide nanostructures have been widely studied due to their potential technological applications. However, the theoretical characterization, especially the effect of the surface on the mechanical properties of this material is still underexplored. In this work, we report the electronic and mechanical properties of 3C-SiC nanopores with different pore surfaces and different passivation schemes using a density functional theory approach and the supercell technique. The nanopores were modeled by removing columns of atoms in the [001] direction, thus creating four types of pores, two with an Only C or Si pore and two with a C or Si-Rich pore surface. All surfaces were passivated with hydrogen, then some atoms of H were replaced with fluorine and chlorine. Results show that pores with a higher concentration of C on the surface have a larger bandgap compared with the Si cases. Moreover, only a few changes can be observed due to passivation. For the mechanical properties the Bulk and Young’s modulus were calculated and show that the Only C structures were the most brittle and, for almost all the pores, the H + Cl passivation improve the Bulk modulus.},

keywords = {DFT, electronic properties, Halogens, Mechanical properties, Porous SiC},

pubstate = {published},

tppubtype = {article}

}

@article{ARELLANO2023106704,

title = {DFT investigation of metal-decorated silicon carbide nanosheets for the adsorption of NH3},

author = {Lucia G. Arellano and Brandom J. Cid and Jos\'{e} E. Santana and Francisco De Santiago and \'{A}lvaro Miranda and Alejandro Trejo and Fernando Salazar and Luis A. P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S2352492823013958},

doi = {https://doi.org/10.1016/j.mtcomm.2023.106704},

issn = {2352-4928},

year  = {2023},

date = {2023-01-01},

journal = {Materials Today Communications},

volume = {36},

pages = {106704},

abstract = {The threat that ammonia (NH3) poses in various human activity environments drives the necessity of sensors of higher sensitivity. Two-dimensional (2D) materials have attracted attention for this particular purpose, with 2D silicon carbide being one prospect for this application. However, this potential use has been relatively unexplored. In this work, we study the adsorption of NH3 on pristine and metal (Li, Na, Mg, Ca, Ag, Au, Cu, Pd, and Ti) decorated silicon carbide monolayers (2D-SiC) using a first-principles approach based on Density-Functional Theory. Energetic analyses were performed to determine the enhancement or deterioration of the NH3 adsorption capacities of the 2D-SiC. The results show that the Ag- and Au-decorated monolayers are the best candidates for NH3 capturing due to the large adsorption energies found in these systems.},

keywords = {2D materials, Ammonia, DFT, Monolayer, Sensor, Silicon carbide},

pubstate = {published},

tppubtype = {article}

}

@article{Sosa2022,

title = {NH3 capture and detection by metal-decorated germanene: a DFT study},

author = {Akari Narayama Sosa and Jos\'{e} Eduardo Santana and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Alejandro Trejo and Fernando Salazar and Miguel Cruz-Irisson},

url = {https://doi.org/10.1007/s10853-022-06955-w},

doi = {10.1007/s10853-022-06955-w},

issn = {1573-4803},

year  = {2022},

date = {2022-05-01},

journal = {Journal of Materials Science},

volume = {57},

number = {18},

pages = {8516-8529},

abstract = {We report an investigation of the adsorption of ammonia (NH3) on pristine, alkali (Li, Na, K), alkaline earth (Mg, Ca), and transition metal (Sc, Pd, and Ag) decorated germanene using a first-principles approach based on density-functional theory (DFT). The most stable adsorption geometries, adsorption energies, and charge transfers of NH3 adsorbed on pristine and metal-decorated germanene are thoroughly discussed. First, the NH3 adsorption on pristine germanene was considered, and subsequently, the NH3 adsorption on metal-decorated germanene was studied. Our calculations found that the NH3 is weakly adsorbed on pristine germanene. All metals improved the adsorption properties of pristine germanene. In particular, Sc, Mg, and Li atoms showed significantly enhanced interactions between NH3 and germanene. In general, the electronic and adsorption properties demonstrated that metal-decorated germanene is superior to pristine germanene for the adsorption of NH3 molecules. Changes in the work function due to adsorption of NH3 molecule on the metal-decorated germanene were also calculated. Adsorption energy and desorption time results show that Sc-decorated germanene could trap this dangerous molecule at room temperature.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/er.8378,

title = {Tunable electronic properties of silicon nanowires as sodium-battery anodes},

author = {Lucia Guadalupe Arellano and Fernando Salazar and \'{A}lvaro Miranda and Alejandro Trejo and Luis Antonio P\'{e}rez and Jun Nakamura and Miguel Cruz-Irisson},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/er.8378},

doi = {https://doi.org/10.1002/er.8378},

year  = {2022},

date = {2022-01-01},

journal = {International Journal of Energy Research},

volume = {46},

number = {12},

pages = {17151-17162},

abstract = {Summary Although materials for lithium-ion batteries have been extensively studied, alternatives such as sodium-ion batteries have acquired a renewed interest due to the abundance of Na compared to Li. However, the investigation of new materials for Na battery anodes is still in progress. In this work, a density functional study of the electronic properties of hydrogen passivated silicon nanowires (H-SiNWs) with interstitial Na atoms is presented. The studied H-SiNWs are grown along the [001] crystallographic direction and have a diameter close to 2.5 nm. Moreover, from 1 to 12 interstitial Na atoms per H-SiNW unit cell were considered. The results reveal that the former semiconducting nanowires become metallic for all the Na concentrations, even for the case of a single Na atom. The formation energy diminishes as a function of the concentration of Na atoms, revealing a loss of energetic stability since the size of the Na atoms strongly modify the Si-Si bonds. Moreover, when the Na atoms are removed from the metallic sodiated H-SiNW and relaxed again, for concentrations between 1 and 8 Na atoms, the resulting structure corresponds to the original H-SiNW one, indicating that the Na insertion/extraction process is a reversible one. In contrast, for concentrations between 10 and 12 Na atoms, the structure that results from removing of these Na atoms has a different atomic arrangement, in comparison with the initial H-SiNW, and also smaller band gap. These results open the possibility to consider the H-SiNWs as potential anodic materials in sodium rechargeable batteries.},

keywords = {DFT, Silicon nanowires, sodium-ion batteries},

pubstate = {published},

tppubtype = {article}

}

@article{CUEVAS2022115372,

title = {Theoretical approach to the phonon modes of GaSb nanowires},

author = {J. L. Cuevas and M. Ojeda and M. Calvino and A. Trejo and F. Salazar and A. Miranda and L. A. Perez and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S1386947722002077},

doi = {https://doi.org/10.1016/j.physe.2022.115372},

issn = {1386-9477},

year  = {2022},

date = {2022-01-01},

journal = {Physica E: Low-dimensional Systems and Nanostructures},

volume = {143},

pages = {115372},

abstract = {Gallium Antimonide nanowires (GaSbNWs) have attracted much attention due to their possible applications in mid infrared detectors, however, there are only few theoretical investigations about this material and almost none regarding its vibrational properties. In this work the phonon modes of GaSbNWs were studied using the density functional theory with the finite displacement supercell scheme. The nanowires are modeled by removing atoms outside from a circumference along the [1 1 1] direction. All surface dangling bonds were passivated with hydrogen atoms. The results show that the expected red-shift of the highest frequency modes of GaSb are hindered by low frequency H bond bending modes. Three clearly distinguishable frequency intervals were observed: One with vibrations whose main contribution come from the Ga and Sb nanowire atoms, the second interval with main contributions from H bending modes and finally a high frequency interval where the main contributions come from H stretching modes. Also, it was observed that the radial breathing mode (RBM) decreases when the nanowire diameter increases, while the contrary tendency is observed with their specific heat (the specific heat increases as the nanowire diameter increases), except in the low temperature region where the lower diameters have higher specific heat values. These results could be important for the characterization of these nanowires with IR and Raman techniques.},

keywords = {DFT, Gallium Antimonide, Nanowires, Phonons},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/er.7754,

title = {Sodium effects on the electronic and structural properties of porous silicon for energy storage},

author = {Israel Gonz\'{a}lez and Jorge Pilo and Alejandro Trejo and \'{A}lvaro Miranda and Fernando Salazar and Roc\'{i}o Nava and Miguel Cruz-Irisson},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/er.7754},

doi = {https://doi.org/10.1002/er.7754},

year  = {2022},

date = {2022-01-01},

journal = {International Journal of Energy Research},

volume = {46},

number = {7},

pages = {8760-8780},

abstract = {Summary Porous silicon is a promising anode material in Na-ion batteries, however, there are still no theoretical studies describing the Na storage mechanism within this material. In this work, we present a density functional theory study on the effects of interstitial and substitutional Na atoms on the electronic and structural properties of hydrogen-passivated porous silicon (pSiH). The results show that the substitutional Na reduces the band gap, while the interstitial Na induces metallic properties on the pSiH. The diffusion analysis by the nudged elastic band scheme, reveals that the interstitial Na atoms migrate from the silicon lattice to the pore surface, while the pSiH energy barrier decreases by 20.42% relative to the bulk silicon energy barrier value. Finally, the hydrogenated surface proves to be beneficial for both Na adsorption and diffusion. These results could be important for understanding the storage and diffusion mechanism of Na on pSiH .},

keywords = {DFT, Na-batteries, NEB, porous silicon},

pubstate = {published},

tppubtype = {article}

}

@article{D1DT04041C,

title = {Impact of alkaline-earth doping on electronic properties of the photovoltaic perovskite CsSnI3: insights from a DFT perspective},

author = {Iv\'{a}n \"{O}rnelas-Cruz and Israel Gonz\'{a}lez and Jorge Pilo and Alejandro Trejo and Ra\'{u}l Oviedo-Roa and Miguel" Cruz-Irisson},

url = {http://dx.doi.org/10.1039/D1DT04041C},

doi = {10.1039/D1DT04041C},

year  = {2022},

date = {2022-01-01},

journal = {Dalton Trans.},

volume = {51},

issue = {17},

pages = {6607-6621},

publisher = {The Royal Society of Chemistry},

abstract = {The oxidation of Sn(ii) to the more stable Sn(iv) degrades the photovoltaic perovskite material CsSnI3; however, this problem can be counteracted via alkaline-earth (AE) doping. In this work, the electronic properties of CsSn1−xAExI3, with x = 0 and 0.25, and AE = Mg and Ca, were investigated via Density Functional Theory. It is proven that the synthetic reactions of all these perovskites are thermodynamically viable. Besides, a slight strengthening in the metal\textendashhalide bonds is found in the Mg-doped perovskite; consequently, it exhibits the greatest bulk modulus. Nevertheless, the opposite occurrs with the Ca-doped perovskite, which has the smallest bulk modulus due to the weakening of its metal\textendashhalide bonds. The calculated bandgaps for CsSnI3, Mg-doped and Ca-doped perovskites are 1.11, 1.32 and 1.55 eV, respectively, remaining remarkably close to the best photovoltaic-performing value for single-junction solar cells of 1.34 eV. Nevertheless, an indirect bandgap was predicted under Mg-doping. These results support the possibility of implementing AE-doped perovskites as absorber materials in single-junction solar cells, which can deliver higher output voltages than that using CsSnI3. Finally, it was found that Sr or Ba doping could result in semiconductors with bandgaps close to 2.0 eV.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{SOSA2021130201,

title = {CO and CO2 adsorption performance of transition metal-functionalized germanene},

author = {Akari Narayama Sosa and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Alejandro Trejo and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0167577X21008983},

doi = {https://doi.org/10.1016/j.matlet.2021.130201},

issn = {0167-577X},

year  = {2021},

date = {2021-01-01},

journal = {Materials Letters},

volume = {300},

pages = {130201},

abstract = {In this work, the pristine and transition metal (TM)-functionalized germanene are investigated for sensing applications. Firstly, the detection of CO and CO2 molecules by pristine germanene is considered, and the numerical results show that adsorption energy values are in the physisorption range. Then, the adsorption of CO and CO2 molecules on Cu-, Ag-, and Au-functionalized germanene is studied. Results show that germanene functionalization with TM atoms considerably improves the interaction towards CO molecule when bound through the C atom [CO(C)], in the chemisorption range. On the other hand, numerical results show that the germanene sensing capabilities for the CO(O) and CO2 molecules do not improve with TM, these were adsorbed in the physisorption interval. Results suggest that the TM-functionalized germanene can have potential uses in CO sensing.},

keywords = {2D materials, Adsorption energy, DFT, Gas sensing, Germanene, Sensors},

pubstate = {published},

tppubtype = {article}

}

@article{ARELLANO202129261,

title = {Ab initio study of hydrogen storage on metal-decorated GeC monolayers},

author = {Lucia Guadalupe Arellano and Francisco De Santiago and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Fernando Salazar and Alejandro Trejo and Jun Nakamura and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S036031992101555X},

doi = {https://doi.org/10.1016/j.ijhydene.2021.04.135},

issn = {0360-3199},

year  = {2021},

date = {2021-01-01},

journal = {International Journal of Hydrogen Energy},

volume = {46},

number = {57},

pages = {29261-29271},

abstract = {Bidimensional nanostructures have been proposed as hydrogen-storage systems owing to their large surface-to-volume ratios. Germanium carbide monolayers (GeC-MLs) can offer attractive opportunities for H2 adsorption compared to graphene. However, this possibility has not been explored in detail. In this work, the adsorption of H2 molecules on GeC-MLs decorated with alkali metal (AM) and alkaline earth metal (AEM) adatoms was investigated using the density functional theory. Results showed that the AM adatoms were chemisorbed on the GeC-ML, whereas AEM adatoms were physisorbed. The H2 molecules presented negligible adsorption energies on the weakly adsorbed AEM adatoms. Conversely, the AM adatoms improved the H2 adsorption, possibly due to a large charge transfer from the adatoms to the GeC-ML. The potassium-decorated GeC-ML exhibited the most optimal H2 storage capacity, adsorbing up to six molecules and with a lower possibility of forming metal clusters than the other studied cases. These results may aid in the development of new efficient hydrogen-storage materials.},

note = {HYDROGEN ENERGY SYSTEMS},

keywords = {2D materials, Alkali metals, DFT, Germanium carbide, Hydrogen storage, Renewable energy},

pubstate = {published},

tppubtype = {article}

}

@article{SOSA202129348,

title = {Light metal functionalized two-dimensional siligene for high capacity hydrogen storage: DFT study},

author = {Akari Narayama Sosa and Brandom Jhoseph Cid and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Fernando Salazar and Alejandro Trejo and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0360319920340246},

doi = {https://doi.org/10.1016/j.ijhydene.2020.10.175},

issn = {0360-3199},

year  = {2021},

date = {2021-01-01},

journal = {International Journal of Hydrogen Energy},

volume = {46},

number = {57},

pages = {29348-29360},

abstract = {In this work, the hydrogen storage capacities of two-dimensional siligene (2D-SiGe) functionalized with alkali metal (AM) and alkali-earth metal (AEM) atoms were studied using density functional theory calculations. One AM (Li, Na, K) or AEM (Be, Mg, Ca) atom was placed on the 2D-SiGe surface, and several H2 molecules were placed in the vicinity of the adatom. The results demonstrate that the most favorable siligene site for the adsorption of Li, Na, K and Be atoms is the hollow site, while for the Mg and Ca atoms is the down site. The AM atoms are the only ones with considerable binding energies on the SiGe nanosheets. Pristine 2D-SiGe slightly adsorbs one H2 molecule per hollow site and, therefore, it is not suitable for hydrogen storage. In some of the AM- and AEM-decorated 2D-SiGe, several hydrogen molecules can be physisorbed. In particular, the Na-, K- and Ca-functionalized 2D-SiGe can adsorb six hydrogen molecules, whereas Li and Mg atoms adsorbed three hydrogen molecules, and the Be adatom only adsorbed one hydrogen molecule. The complexes formed by hydrogen molecules adsorbed on the analyzed metal decorated 2D-SiGe are energetically stable, indicating that functionalized 2D-SiGe could be an efficient molecular hydrogen storage media.},

note = {HYDROGEN ENERGY SYSTEMS},

keywords = {2D materials, Alkali metals, DFT, Hydrogen storage, Renewable energy, Siligene},

pubstate = {published},

tppubtype = {article}

}

@article{SOSA202120245,

title = {Alkali and transition metal atom-functionalized germanene for hydrogen storage: A DFT investigation},

author = {Akari Narayama Sosa and Francisco Santiago and \'{A}lvaro Miranda and Alejandro Trejo and Fernando Salazar and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0360319920315329},

doi = {https://doi.org/10.1016/j.ijhydene.2020.04.129},

issn = {0360-3199},

year  = {2021},

date = {2021-01-01},

journal = {International Journal of Hydrogen Energy},

volume = {46},

number = {38},

pages = {20245-20256},

abstract = {In this work, we have performed density functional theory-based calculations to study the adsorption of H2 molecules on germanene decorated with alkali atoms (AM) and transition metal atoms (TM). The cohesive energy indicates that interaction between AM (TM) atoms and germanene is strong. The values of the adsorption energies of H2 molecules on the AM or TM atoms are in the range physisorption. The K-decorated germanene has the largest storage capacity, being able to bind up to six H2 molecules, whereas the Au and Na atoms adsorbed five and four H2 molecules, respectively. Li and Ag atoms can bind a maximum of three H2 molecules, while Cu-decorated germanene only adsorbed one H2 molecule. Formation energies show that all the studied cases of H2 molecules adsorbed on AM and TM atom-decorated germanene are energetically favorable. These results indicate that decorated germanene can serve as a hydrogen storage system.},

note = {International Journal of Hydrogen Energy Special Issue devoted to the 32nd International Conference ECOS 2019},

keywords = {2D materials, Decoration, Density Functional Theory, Germanene, Hydrogen storage, Renewable energy storage},

pubstate = {published},

tppubtype = {article}

}

@article{ARELLANO202120266,

title = {Hydrogen storage capacities of alkali and alkaline-earth metal atoms on SiC monolayer: A first-principles study},

author = {Luc\'{i}a G. Arellano and Francisco Santiago and \'{A}lvaro Miranda and Fernando Salazar and Alejandro Trejo and Luis A. P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0360319920310144},

doi = {https://doi.org/10.1016/j.ijhydene.2020.03.078},

issn = {0360-3199},

year  = {2021},

date = {2021-01-01},

journal = {International Journal of Hydrogen Energy},

volume = {46},

number = {38},

pages = {20266-20279},

abstract = {A detailed theoretical Density-Functional-Theory-based investigation of hydrogen adsorption on silicon carbide monolayers (SiC-ML) decorated with alkali and alkaline-earth metal atoms is presented. The results show that the favourable position for all adsorbed metal atoms is above a Si atom. These metal atoms are chemisorbed to the SiC-ML, except for Mg which is physisorbed. The adsorbed atoms act in turn as adsorption sites for H2 molecules. The single-sided K-functionalized SiC-ML can store up to six H2 molecules. For double-side K-decorated SiC-ML, up to ten H2 molecules can be captured. In all cases, the H2 molecules are physisorbed. This is beneficial because the breaking of chemical bonds, which otherwise would be needed to make use of the stored H2, is energetically expensive. These results find decorated SiC-ML as a promising material for hydrogen storage systems.},

note = {International Journal of Hydrogen Energy Special Issue devoted to the 32nd International Conference ECOS 2019},

keywords = {2D monolayers, Adsorption energy, DFT, Hydrogen storage, Silicon carbide},

pubstate = {published},

tppubtype = {article}

}

@article{D0MA00884B,

title = {Fluorinated porous silicon as sensor material for environmentally toxic gases: a first-principles study},

author = {Jos\'{e} Eduardo Santana and Francisco Santiago and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Fernando Salazar and Alejandro Trejo and Miguel Cruz-Irisson},

url = {http://dx.doi.org/10.1039/D0MA00884B},

doi = {10.1039/D0MA00884B},

year  = {2021},

date = {2021-01-01},

journal = {Mater. Adv.},

volume = {2},

issue = {3},

pages = {1072-1082},

publisher = {RSC},

abstract = {By using Density Functional Theory, the effect of adsorbed gas molecules on the electronic properties of fluorine passivated porous silicon (pSi) is investigated. A silicon nanopore is created by removing columns of atoms along the [001] crystallographic axis from a supercell of the bulk Si crystal. The Si dangling bonds of the generated pore are saturated with fluorine atoms except for the sites where gas molecules of NO, NO2 and SO2 are adsorbed. The adsorption energies, electronic densities of states and band structures of the different complexes formed by the nanopore and the adsorbed molecules are calculated and compared with previously reported results obtained for hydrogen-passivated pSi. The energy band gaps of the pSi-molecule complexes depend on the adsorbed species, opening the possibility of gas molecule recognition. The molecule adsorption energy is stronger for NO2. The understanding of molecule adsorption on silicon nanopores could lead to the development of novel sensing devices of environmentally hazardous gases.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bermeo_2020,

title = {Effects of Surface in the IR and Raman Spectrum of Porous Silicon Carbide},

author = {R Bermeo and L. Arellano and A Trejo and F Salazar and M. Calvino and A Miranda and M Cruz-Irisson},

url = {https://dx.doi.org/10.1088/1757-899X/840/1/012009},

doi = {10.1088/1757-899X/840/1/012009},

year  = {2020},

date = {2020-05-01},

journal = {IOP Conference Series: Materials Science and Engineering},

volume = {840},

number = {1},

pages = {012009},

publisher = {IOP Publishing},

abstract = {Porous Silicon carbide has been identified as an attractive material for its use as electrode in supercapacitors, however the theoretical investigations about its properties, specially its vibrational properties, are still scarce. In this work the effect of the Si-C surface ratio on the vibrational properties, IR and Raman spectrum of porous silicon carbide was studied using the first principles density functional perturbation theory. The porous structures were modelled by removing atoms in the [001] direction from an otherwise perfect SiC crystal using the supercell scheme. The morphology of the pores was chosen so there would be more Si or C in the pore surface. The results show that the vibrational properties, and thus the IR and Raman spectrum of the porous SiC change depending if the pore surface is either Si or C rich, having the Si-rich pores more low frequency modes due to its higher mass. Also, the effects of phonon confinement are lessened by the effect of surface passivation, thus indicating that the surface plays an important role in the IR and Raman characterization of these structures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Arellano_2020,

title = {Electronic properties of [111] hydrogen passivated Ge nanowires with surface substitutional lithium},

author = {L G Arellano and F Salazar and A Trejo Ba\~{n}os and A Miranda and L A P\'{e}rez and M Cruz-Irisson},

url = {https://dx.doi.org/10.1088/1757-899X/840/1/012004},

doi = {10.1088/1757-899X/840/1/012004},

year  = {2020},

date = {2020-05-01},

journal = {IOP Conference Series: Materials Science and Engineering},

volume = {840},

number = {1},

pages = {012004},

publisher = {IOP Publishing},

abstract = {In this work, a density functional theory study of the lithium (Li) effects on the properties of hydrogenated germanium nanowires (H-GeNWs) is developed. In particular, the electronic band structures, densities of states, formation energies, and Li binding energies of H-GeNWs grown along the [111] crystallographic direction with a diamond structure for different concentrations of surface substitutional Li atoms were studied. Ge nanowires with hexagonal cross sections and three different diameters were considered. The results indicate that all studied H-GeNWs maintain a semiconducting behaviour and the size of the energy band gap is a function of the diameter and the concentration of substitutional surface Li atoms. The formation energy analysis reveals than the energy stability of the nanowires increases when the nanowire diameter and the concentration of Li atoms augment. The results of this work give insight of how the electronic properties of H-GeNWs change during the charging process and open the possibility to incorporate them as electrodes in Li-ion batteries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ORNELASCRUZ2020109619,

title = {DFT-based study of the bulk tin mixed-halide CsSnI3-xBrx perovskite},

author = {I. Ornelas-Cruz and A. Trejo and R. Oviedo-Roa and F. Salazar and E. Carvajal and A. Miranda and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0927025620301105},

doi = {https://doi.org/10.1016/j.commatsci.2020.109619},

issn = {0927-0256},

year  = {2020},

date = {2020-01-01},

journal = {Computational Materials Science},

volume = {178},

pages = {109619},

abstract = {Metal-halide perovskites compounds, such as CsSnX3 (X = halogen), have attracted a lot of attention as a photovoltaic material due to their astonishing optoelectronic properties, nevertheless, the improvement of its efficiency is still an issue. It has been observed that the mixing of halogens in the perovskite structure increases the compound stability. However, theoretical studies of the effects of this mixing are scarce; by understanding the most stable mixing positions it would be possible to enhance the stability of these structures, which in turn it would help to enhance the performance of a perovskite-based photovoltaic device. Thus, a Density Functional Theory study was performed on the CsSnI3-xBrx perovskite as a function of the bromine concentration (0 ≤ x ≤ 3). The distortions of the octahedral array and the energy gap of each system studied are highly dependent on the position of bromine atoms within the unit-cell. It was observed that stable compounds could be found at x = 0.5, 1.0, and 2.0 due to the strengthening of the metal-halogen bonds. These results could explain the literature-reported enhance of the performance, as a photovoltaic material, of CsSnI3-xBrx with respect to CsSnI3. Besides, non-covalent interactions between halogens and Cs atoms were found. Different energies attributed to such interactions were calculated and revealed that the off-centering of Cs atoms are driven by the countering effect of the I-(1−δ)-Sn-Br-(1+δ) polar bonds within CsSnI3-xBrx. These results give an insight of the properties of the CsSnI3-xBrx alloy and its stability which could be beneficial to the rising field of perovskite photovoltaics.},

keywords = {DFT, Metal-halide, Mixed-halide, Perovskite, Photovoltaic},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZ202026321,

title = {Theoretical modelling of porous silicon decorated with metal atoms for hydrogen storage},

author = {Israel Gonz\'{a}lez and Francisco De Santiago and Luc\'{i}a G. Arellano and \'{A}lvaro Miranda and Alejandro Trejo and Fernando Salazar and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0360319920318784},

doi = {https://doi.org/10.1016/j.ijhydene.2020.05.097},

issn = {0360-3199},

year  = {2020},

date = {2020-01-01},

journal = {International Journal of Hydrogen Energy},

volume = {45},

number = {49},

pages = {26321-26333},

abstract = {There is experimental evidence suggesting that metal adatoms enhance the physisorption of hydrogen molecules in porous silicon. However, theoretical reports about the physical properties for this material to be suitable for hydrogen storage are scarce. Thus, in this work we employ Density Functional Theory to study the effects of decoration with metals on the hydrogen-adsorption properties on hydrogen-passivated porous silicon. The results indicate that lithium and palladium decorating atoms are strongly bonded to the porous silicon\textemdashpreventing the adverse effects of clusterization\textemdashwhile beryllium is not. Lithium and palladium exhibit physisorption capacity up to 5 and 4 hydrogen molecules per adatom, respectively. In contrast, adsorption of hydrogen molecules in beryllium is too weak as the adatom is not chemisorbed on the surface of the pore. The hydrogen passivation of the pore surface proves to be beneficial for a strong chemisorption of the decorating atoms.},

note = {Progress in Hydrogen Production and Utilization},

keywords = {Beryllium, DFT, Hydrogen storage, Lithium, Palladium, porous silicon},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/jcc.26421,

title = {Effects of lithium on the electronic properties of porous Ge as anode material for batteries},

author = {Akari Narayama Sosa and Israel Gonz\'{a}lez and Alejandro Trejo and \'{A}lvaro Miranda and Fernando Salazar and Miguel Cruz-Irisson},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.26421},

doi = {https://doi.org/10.1002/jcc.26421},

year  = {2020},

date = {2020-01-01},

journal = {Journal of Computational Chemistry},

volume = {41},

number = {31},

pages = {2653-2662},

abstract = {Abstract Recently, the need of improvement of energy storage has led to the development of Lithium batteries with porous materials as electrodes. Porous Germanium (pGe) has shown promise for the development of new generation Li-ion batteries due to its excellent electronic, and chemical properties, however, the effect of lithium in its properties has not been studied extensively. In this contribution, the effect of surface and interstitial Li on the electronic properties of pGe was studied using a first-principles density functional theory scheme. The porous structures were modeled by removing columns of atoms in the [001] direction and the surface dangling bonds were passivated with H atoms, and then replaced with Li atoms. Also, the effect of a single interstitial Li in the Ge was analyzed. The transition state and the diffusion barrier of the Li in the Ge structure were studied using a quadratic synchronous transit scheme.},

keywords = {Density Functional Theory, electronic properties, Li-ion batteries, porous germanium, transition state},

pubstate = {published},

tppubtype = {article}

}

@article{Gonz\'{a}lez_2019,

title = {Confinement effect on the low temperature specific heat for ultrathin silicon nanowires: a first principles study},

author = {I Gonz\'{a}lez and M Calvino and A Trejo and F Salazar and M Cruz-Irisson},

url = {https://dx.doi.org/10.1088/1361-648X/ab2dd4},

doi = {10.1088/1361-648X/ab2dd4},

year  = {2019},

date = {2019-07-01},

journal = {Journal of Physics: Condensed Matter},

volume = {31},

number = {42},

pages = {425303},

publisher = {IOP Publishing},

abstract = {This work studied the phonon confinement effects at the low temperature specific heat of Si nanowires from first principles using density functional perturbation theory. The nanowires were modeled in the [0 0 1] direction for three different diameters, with the largest cross section being approximately 10 r{A}. The results indicate the specific heat can be described at low temperatures using a third-grade polynomial of the form cv = λT + βT2 + γT3, where the coefficients of quadratic and cubic terms are almost nonexistent for small diameters. These terms begin to have relevance at larger diameters. Further analysis shows λ > β > γ, which shows the phonon confinement (λ) and surface atoms (β) become more important than the volumetric contribution (γ) for ultrathin nanowires at low temperatures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DESANTIAGO2019278,

title = {Quasi-one-dimensional silicon nanostructures for gas molecule adsorption: a DFT investigation},

author = {Francisco Santiago and Jos\'{e} Eduardo Santana and \'{A}lvaro Miranda and Alejandro Trejo and Rub\'{e}n V\'{a}zquez-Medina and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0169433218336109},

doi = {https://doi.org/10.1016/j.apsusc.2018.12.258},

issn = {0169-4332},

year  = {2019},

date = {2019-01-01},

journal = {Applied Surface Science},

volume = {475},

pages = {278-284},

abstract = {Porous structures offer an enormous surface suitable for gas sensing, however, the effects of their quantum quasi-confinement on their molecular sensing capacities has been seldom studied. In this work the gas-sensing capability of silicon nanopores is investigated by comparing it to silicon nanowires using first principles calculations. In particular, the adsorption of toxic gas molecules CO, NO, SO2 and NO2 on both silicon nanopores and nanowires with the same cross sections was studied. Results show that sensing-related properties of silicon nanopores and nanowires are very similar, suggesting that surface effects are predominant over the confinement. However, there are certain cases where there are remarked differences between the nanowire and porous cases, for instance, CO-adsorbed nanoporous silicon shows a metallic band structure unlike its nanowire counterpart, which remains semiconducting, suggesting that quantum quasi-confinement may be playing an important role in this behaviour. These results are significant in the study of the quantum phenomena behind the adsorption of gas molecules on nanostructure’s surfaces, with possible applications in chemical detectors or catalysts.},

keywords = {Chemical sensors, Density Functional Theory, Molecule adsorption, porous silicon, Sensing, Silicon nanowires},

pubstate = {published},

tppubtype = {article}

}

@article{DESANTIAGO2019438,

title = {Lithiation effects on the structural and electronic properties of Si nanowires as a potential anode material},

author = {F. De Santiago and J. E. Gonz\'{a}lez and A. Miranda and A. Trejo and F. Salazar and L. A. P\'{e}rez and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S2405829718313254},

doi = {https://doi.org/10.1016/j.ensm.2019.04.023},

issn = {2405-8297},

year  = {2019},

date = {2019-01-01},

journal = {Energy Storage Materials},

volume = {20},

pages = {438-445},

abstract = {The need for better energy-storage materials has attracted much attention to the development of Li-ion battery electrodes. Si nanowires have been considered as alternative electrodes, however the effects of Li on their electronic band gap and mechanical properties have been scarcely studied. In this work, a density functional study of the electronic and mechanical properties of hydrogen passivated silicon nanowires (H-SiNWs) grown along the [001] direction is presented. The Li atoms are gradually inserted at interstitial positions or replacing surface H atoms. The results show that, for surface-lithiated H-SiNWs, the semiconducting band gap decreases when the concentration of Li atoms increases; whereas the H-SiNWs become metallic even with the addition of only one interstitial Li atom. The formation energy diminishes with the concentration of Li atoms for surface-lithiated H-SiNWs, whereas the contrary behavior is found in the interstitial-lithiated H-SiNWs. Furthermore, for the surface-lithiation case, the Li binding energy reveals the existence of SiLi bonds, whereas for the interstitial-lithiation case, the Li binding energy increases when the Li grows up to a critical concentration, where some SiSi bonds break. Finally, for the case of surface-lithiation, the Young's modulus (Y) increases with the concentration of Li, whereas for the interstitial-lithiation case, Y suffers a sudden diminution at a certain Li concentration due to the large internal mechanical stresses within the nanowire structure. These results should be considered when regarding H-SiNWs as potential electrodes in Li-ion battery anodes.},

keywords = {electronic properties, Li batteries, Silicon nanowires, Young's modulus},

pubstate = {published},

tppubtype = {article}

}

@article{Gonz\'{a}lez-Mac\'{i}as2018,

title = {Theoretical study of the mechanical and electronic properties of [111]-Si nanowires with interstitial lithium},

author = {A. Gonz\'{a}lez-Mac\'{i}as and F. Salazar and A. Miranda and A. Trejo and I. J. Hern\'{a}ndez-Hern\'{a}ndez and L. A. P\'{e}rez and M Cruz-Irisson},

url = {https://doi.org/10.1007/s10854-018-9331-6},

doi = {10.1007/s10854-018-9331-6},

issn = {1573-482X},

year  = {2018},

date = {2018-09-01},

journal = {Journal of Materials Science: Materials in Electronics},

volume = {29},

number = {18},

pages = {15795-15800},

abstract = {In this work, we present a density functional study of the Young's modulus and electronic properties of hydrogen passivated silicon nanowires (H-SiNWs) grown along [111] crystallographic direction as function of concentration of interstitial lithium (Li) atoms. The study is performed using the supercell scheme, within the local density approximation implemented in the SIESTA code. The results show that the presence of Li closes the known semiconductor band gap of the H-SiNWs showing a like metallic behavior even when just one Li atom is placed in the nanowire structure. The participation of the Li atoms in the electronic density of states is almost constant in the valence and conduction bands. The formation energy analysis show how the system loses energetic stability when the concentration of Li grows, while the binding energy per Li atom suggests the formation of Si--Li bonds. On the other hand, the Young's modulus of the silicon nanowires (SiNWs) is higher than that of the H-SiNW and lower than the bulk value. Moreover, the Young's modulus is almost constant independently of the Li concentration. This result indicates that the H-SiNWs support the internal stress due to the addition of Li atoms and could offer a better useful life as electrodes in Li-ion batteries. The results of this work help to understand how the electronic and mechanical properties of H-SiNWs change during the charge/discharge process and the possibility to incorporate them as electrodes in Li batteries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{deSantiago_2018,

title = {Carbon monoxide sensing properties of B-, Al- and Ga-doped Si nanowires},

author = {F Santiago and A Trejo and A Miranda and F Salazar and E Carvajal and L A P\'{e}rez and M Cruz-Irisson},

url = {https://dx.doi.org/10.1088/1361-6528/aab237},

doi = {10.1088/1361-6528/aab237},

year  = {2018},

date = {2018-03-01},

journal = {Nanotechnology},

volume = {29},

number = {20},

pages = {204001},

publisher = {IOP Publishing},

abstract = {Silicon nanowires (SiNWs) are considered as potential chemical sensors due to their large surface-to-volume ratio and their possible integration into arrays for nanotechnological applications. Detection of harmful gases like CO has been experimentally demonstrated, however, the influence of doping on the sensing capacity of SiNWs has not yet been reported. For this work, we theoretically studied the surface adsorption of a CO molecule on hydrogen-passivated SiNWs grown along the [111] crystallographic direction and compared it with the adsorption of other molecules such as NO, and O2. Three nanowire diameters and three dopant elements (B, Al and Ga) were considered, and calculations were done within the density functional theory framework. The results indicate that CO molecules are more strongly adsorbed on the doped SiNW than on the pristine SiNW. The following trend was observed for the CO adsorption energies: EA[B-doped] > EA[Al-doped] > EA[Ga-doped] > EA[undoped], for all diameters. The electronic charge transfers between the SiNWs and the adsorbed CO were estimated by using a Voronoi population analysis. The CO adsorbed onto the undoped SiNWs has an electron-acceptor character, while the CO adsorbed onto the B-, Al-, and Ga-doped SiNWs exhibits an electron-donor character. Comparing these results with the ones obtained for the NO and O2 adsorption, the larger CO adsorption energy on B-doped SiNWs indicates their good selectivity towards CO. These results suggest that SiNW-based sensors of toxic gases could represent a clear and advantageous application of nanotechnology in the improvement of human quality of life.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gonz\'{a}lez-Mac\'{i}as_2018,

title = {Lithium effects on the mechanical and electronic properties of germanium nanowires},

author = {A Gonz\'{a}lez-Mac\'{i}as and F Salazar and A Miranda and A Trejo-Ba\~{n}os and L A P\'{e}rez and E Carvajal and M Cruz-Irisson},

url = {https://dx.doi.org/10.1088/1361-6528/aaaad4},

doi = {10.1088/1361-6528/aaaad4},

year  = {2018},

date = {2018-02-01},

journal = {Nanotechnology},

volume = {29},

number = {15},

pages = {154004},

publisher = {IOP Publishing},

abstract = {Semiconductor nanowire arrays promise rapid development of a new generation of lithium (Li) batteries because they can store more Li atoms than conventional crystals due to their large surface areas. During the charge\textendashdischarge process, the electrodes experience internal stresses that fatigue the material and limit the useful life of the battery. The theoretical study of electronic and mechanical properties of lithiated nanowire arrays allows the designing of electrode materials that could improve battery performance. In this work, we present a density functional theory study of the electronic band structure, formation energy, binding energy, and Young’s modulus (Y) of hydrogen passivated germanium nanowires (H\textendashGeNWs) grown along the [111] and [001] crystallographic directions with surface and interstitial Li atoms. The results show that the germanium nanowires (GeNWs) with surface Li atoms maintain their semiconducting behavior but their energy gap size decreases when the Li concentration grows. In contrast, the GeNWs can have semiconductor or metallic behavior depending on the concentration of the interstitial Li atoms. On the other hand, Y is an indicator of the structural changes that GeNWs suffer due to the concentration of Li atoms. For surface Li atoms, Y stays almost constant, whereas for interstitial Li atoms, the Y values indicate important structural changes in the GeNWs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{C8DT00355F,

title = {Lithium effect on the electronic properties of porous silicon for energy storage applications: a DFT study},

author = {I. Gonz\'{a}lez and A. N. Sosa and A. Trejo and M. Calvino and A. Miranda and M. Cruz-Irisson},

url = {http://dx.doi.org/10.1039/C8DT00355F},

doi = {10.1039/C8DT00355F},

year  = {2018},

date = {2018-01-01},

journal = {Dalton Trans.},

volume = {47},

issue = {22},

pages = {7505-7514},

publisher = {The Royal Society of Chemistry},

abstract = {Theoretical studies on the effect of Li on the electronic properties of porous silicon are still scarce; these studies could help us in the development of Li-ion batteries of this material which overcomes some limitations that bulk silicon has. In this work, the effect of interstitial and surface Li on the electronic properties of porous Si is studied using the first-principles density functional theory approach and the generalised gradient approximation. The pores are modeled by removing columns of atoms of an otherwise perfect Si crystal, dangling bonds of all surfaces are passivated with H atoms, and then Li is inserted on interstitial positions on the pore wall and compared with the replacement of H atoms with Li. The results show that the interstitial Li creates effects similar to n-type doping where the Fermi level is shifted towards the conduction band with band crossings of the said level thus acquiring metallic characteristics. The surface Li introduces trap-like states in the electronic band structures which increase as the number of Li atom increases with a tendency to become metallic. These results could be important for the application of porous Si nanostructures in Li-ion batteries technology.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{CUEVAS2018268,

title = {First principles band gap engineering of [1 1 0] oriented 3C-SiC nanowires},

author = {Jos\'{e} Luis Cuevas and Francisco Santiago and Jes\'{u}s Ram\'{i}rez and Alejandro Trejo and \'{A}lvaro Miranda and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0927025617305712},

doi = {https://doi.org/10.1016/j.commatsci.2017.10.021},

issn = {0927-0256},

year  = {2018},

date = {2018-01-01},

journal = {Computational Materials Science},

volume = {142},

pages = {268-276},

abstract = {Silicon carbide nanowires offer excellent opportunities for technological applications under harsh environmental conditions, however, the 3C-SiC polytype nanowires, grown along the [1 1 0] crystallographic direction, have been rarely studied, as well as the effects of the surface passivation on their physical properties. This work addresses the effects of hydrogen passivation on the electronic band gap of silicon carbide nanowires (SiCNWs) grown along the [1 1 0] direction by means of Density Functional Theory. We compare the electronic properties of fully hydrogen-passivated SiCNWs in comparison to those of SiCNWs with a mixed passivation of oxygen and hydrogen by changing some of the surface dihydrides with SiOSi or COC bonds. The results show that regardless of the diameter and passivation, most of the nanowires have a direct band gap which suggests an increased optical activity. The surface COC bonds reduce the electronic band gap energy compared to that of the fully H-terminated phase, while the nanowires with SiOSi bonds have a larger band gap. The calculation of formation energies shows that the oxygen increases the chemical stability of the SiCNWs. These results indicate the possibility of band gap engineering on SiC nanostructures through surface passivation.},

keywords = {DFT, Formation energy, SiC nanowires, Surface passivation},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/qua.25713,

title = {Quantum confinement effects on the harmful-gas-sensing properties of silicon nanowires},

author = {Francisco Santiago and \'{A}lvaro Miranda and Alejandro Trejo and Fernando Salazar and Eliel Carvajal and Miguel Cruz-Irisson and Luis A. P\'{e}rez},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/qua.25713},

doi = {https://doi.org/10.1002/qua.25713},

year  = {2018},

date = {2018-01-01},

journal = {International Journal of Quantum Chemistry},

volume = {118},

number = {20},

pages = {e25713},

abstract = {Abstract In this work, the effects of the adsorption of different toxic gas molecules CO, NO, NO2, and SO2 on the electronic structure of hydrogen-passivated, [111]-oriented, silicon nanowires (H-SiNWs), are studied through density functional theory. To analyze the effects of quantum confinement, three nanowire diameters are considered. The results show that the adsorption energies are almost independent of the nanowire diameter with NO2 being the most strongly adsorbed molecule (∼3.44 eV). The electronic structure of small-diameter H-SiNWs is modified due to the creation of isolated defect-like states on molecule adsorption. However, these discrete levels are eventually hybridized with the former nanowire states as the nanowire diameter increases and quantum confinement effects become less evident. Hence, there is a range of small nanowire diameters with distinctive band gaps and adsorption energies for each molecule species.},

keywords = {Density Functional Theory, Nanowires, Sensors, silicon, toxic gases},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZ2018420,

title = {Effects of surface and confinement on the optical vibrational modes and dielectric function of 3C porous silicon carbide: An ab-initio study},

author = {I. Gonz\'{a}lez and A. Trejo and M. Calvino and A. Miranda and F. Salazar and E. Carvajal and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0921452618303569},

doi = {https://doi.org/10.1016/j.physb.2018.05.024},

issn = {0921-4526},

year  = {2018},

date = {2018-01-01},

journal = {Physica B: Condensed Matter},

volume = {550},

pages = {420-427},

abstract = {Nanoporous silicon carbide is an interesting material with multiple potential applications, especially in supercapacitors, while there are many experimental investigations on the properties of this material, theoretical studies on its vibrational and optical properties are still scarce. This work studies the effect of quantum confinement on the dielectric function and optical vibrational modes of 3C porous silicon carbide from ab-initio calculations using density functional theory and density functional perturbation theory. The porous structures are modelled in the [001] direction by removing columns of atoms of a perfect Si crystal, obtaining two surface configurations: one with only C atoms and another one with Si atoms. Results show that the optical phonon modes of Si and C undergo a shift towards lower frequencies compared to their bulk counterparts due to phonon confinement effects. However, this shift is masked by H bending vibrations. Also, a surface H exchange process is observed on the Si-rich pore surface due to bond stretching and bending vibrations. The dielectric function analysis shows an increased optical activity in the porous cases due to a shift of the conduction band minimum towards gamma point for the C-rich case and high porosity Si-rich case, owing to quantum confinement effects. These results could be important for the applications of these nanostructures devices such as sensors and UV detectors.},

keywords = {DFPT, Dielectric function, Phonon optical modes, Porous silicon carbide},

pubstate = {published},

tppubtype = {article}

}

@article{Pilo2017,

title = {Bidimensional perovskite systems for spintronic applications},

author = {Jorge Pilo and \'{A}lvaro Miranda and Alejandro Trejo and Eliel Carvajal and Miguel Cruz-Irisson},

url = {https://doi.org/10.1007/s00894-017-3483-9},

doi = {10.1007/s00894-017-3483-9},

issn = {0948-5023},

year  = {2017},

date = {2017-10-24},

journal = {Journal of Molecular Modeling},

volume = {23},

number = {11},

pages = {322},

abstract = {The half-metallic behavior of the perovskite Sr2FeMoO6 (SFMO) suggests that this material could be used in spintronic applications. Indeed, SFMO could be an attractive material for multiple applications due to the possibility that its electronic properties could be changed by modifying its spatial confinement or the relative contents of its constituent transition metals. However, there are no reports of theoretical studies on the properties of confined SFMOs with different transition metal contents. In this work, we studied the electronic properties of SFMO slabs using spin-polarized first-principles density functional theory along with the Hubbard-corrected local density approximation and a supercell scheme. We modeled three insulated SFMO slabs with Fe:Mo atomic ratios of 1:1, 1:0, and 0:1; all with free surfaces parallel to the (001) crystal plane. The results show that the half-metallicity of the SFMO is lost upon confinement and the material becomes a conductor, regardless of the ratio of Fe to Mo. It was also observed that the magnetic moment of the slab is strongly influenced by the oxygen atoms. These results could prove useful in attempts to apply SFMOs in fields other than spintronics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{deSantiago2017,

title = {Band-gap engineering of halogenated silicon nanowires through molecular doping},

author = {Francisco Santiago and Alejandro Trejo and Alvaro Miranda and Eliel Carvajal and Luis Antonio P\'{e}rez and Miguel Cruz-Irisson},

url = {https://doi.org/10.1007/s00894-017-3484-8},

doi = {10.1007/s00894-017-3484-8},

issn = {0948-5023},

year  = {2017},

date = {2017-10-16},

journal = {Journal of Molecular Modeling},

volume = {23},

number = {11},

pages = {314},

abstract = {In this work, we address the effects of molecular doping on the electronic properties of fluorinated and chlorinated silicon nanowires (SiNWs), in comparison with those corresponding to hydrogen-passivated SiNWs. Adsorption of n-type dopant molecules on hydrogenated and halogenated SiNWs and their chemisorption energies, formation energies, and electronic band gap are studied by using density functional theory calculations. The results show that there are considerable charge transfers and strong covalent interactions between the dopant molecules and the SiNWs. Moreover, the results show that the energy band gap of SiNWs changes due to chemical surface doping and it can be further tuned by surface passivation. We conclude that a molecular based ex-situ doping, where molecules are adsorbed on the surface of the SiNW, can be an alternative path to conventional doping.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Solano2017,

title = {DFT study of anisotropy effects on the electronic properties of diamond nanowires with nitrogen-vacancy center},

author = {Jes\'{u}s Ram\'{i}rez Solano and Alejandro Trejo Ba\~{n}os and \'{A}lvaro Miranda Dur\'{a}n and Eliel Carvajal Quiroz and Miguel Cruz Irisson},

url = {https://doi.org/10.1007/s00894-017-3462-1},

doi = {10.1007/s00894-017-3462-1},

issn = {0948-5023},

year  = {2017},

date = {2017-09-26},

journal = {Journal of Molecular Modeling},

volume = {23},

number = {10},

pages = {292},

abstract = {In the development of quantum computing and communications, improvements in materials capable of single photon emission are of great importance. Advances in single photon emission have been achieved experimentally by introducing nitrogen-vacancy (N-V) centers on diamond nanostructures. However, theoretical modeling of the anisotropic effects on the electronic properties of these materials is almost nonexistent. In this study, the electronic band structure and density of states of diamond nanowires with N-V defects were analyzed through first principles approach using the density functional theory and the supercell scheme. The nanowires were modeled on two growth directions [001] and [111]. All surface dangling bonds were passivated with hydrogen (H) atoms. The results show that the N-V introduces multiple trap states within the energy band gap of the diamond nanowire. The energy difference between these states is influenced by the growth direction of the nanowires, which could contribute to the emission of photons with different wavelengths. The presence of these trap states could reduce the recombination rate between the conduction and the valence band, thus favoring the single photon emission.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Calvino2016,

title = {Modeling the effects of Si-X (X = F, Cl) bonds on the chemical and electronic properties of Si-surface terminated porous 3C-SiC},

author = {Marbella Calvino and Alejandro Trejo and Margarita Clarisaila Cris\'{o}stomo and Mar\'{i}a Isabel Iturrios and Eliel Carvajal and M Cruz-Irisson},

url = {https://doi.org/10.1007/s00214-016-1861-5},

doi = {10.1007/s00214-016-1861-5},

issn = {1432-2234},

year  = {2016},

date = {2016-03-26},

journal = {Theoretical Chemistry Accounts},

volume = {135},

number = {4},

pages = {104},

abstract = {Porous silicon carbide offers a great potential as a sensor material for applications in medicine and energetics; however, the theoretical chemical characterization of its surface is almost nonexistent, and a correct understanding of its chemical properties could lead to the development of better applications of this nanostructure. Hence, a study of the effects of different passivation agents on the structure and electronic properties of porous silicon carbide by means of density functional theory and the supercell technique was developed. The porous structures were modeled by removing columns of atoms of an otherwise perfect SiC crystal in the [001] direction, so that the porous structure exhibits a surface exclusively composed of Si atoms (Si-rich) using different surface passivation agents, such as hydrogen (H), fluoride (F) and chloride (Cl). The results demonstrate that all of the passivation schemes exhibit an irregular band gap energy evolution due to a hybridization change of the surface. The structural analysis shows a great dependence of the bond characteristics on the electronegativity of the bonded atoms, and all of the structural and electronic changes could be explained due to steric effects. These results could be important in the characterization of pSiC because they provide insight into the most stable surface configurations and their electronic structures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TREJO2016215,

title = {Optical vibrational modes of Ge nanowires: A computational approach},

author = {A. Trejo and A. Miranda and L. K. Toscano-Medina and R. V\'{a}zquez-Medina and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0167931716302258},

doi = {https://doi.org/10.1016/j.mee.2016.04.024},

issn = {0167-9317},

year  = {2016},

date = {2016-01-01},

journal = {Microelectronic Engineering},

volume = {159},

pages = {215-220},

abstract = {Although Ge nanowires (GeNWs) have been extensively studied in the last decade the information about their vibrational modes is still scarce, their correct comprehension could hasten the development of new microelectronic technologies, therefore, in this work we aimed to study the vibrational properties, Raman and IR and spectrum of GeNWs using the first principles density functional perturbation theory. The nanowires are modelled in the [001] direction and all dangling bonds are passivated with H and Cl atoms. Results show that the vibrational modes can be classified in three frequency intervals, a low frequency one (between 0 and 300cm−1) of mainly GeGe vibrations, and two of GeH bending and stretching vibrations (400\textendash500cm−1 and 2000cm−1, respectively). There is a shift of the highest optical modes of GeGe vibrations compared to their bulk counterparts due to phonon confinement effects, however it is masked by some GeH bond bending modes as demonstrated by the IR and Raman responses. The Cl passivated case shows a larger number of modes at lower frequencies due to the higher mass of Cl compared to H, which in turn reduces the red shift of the highest optical modes frequencies. These results could be important for the characterization of GeNWs with different surface passivations.},

note = {Micro/Nano Devices and Systems 2015},

keywords = {Density functional perturbation theory, Germanium nanowires, Phonons, Raman spectrum},

pubstate = {published},

tppubtype = {article}

}

@article{PILO2016110,

title = {Effect of the transition metal ratio on bulk and thin slab double perovskite Sr2FeMoO6},

author = {J. Pilo and A. Trejo and E. Carvajal and R. Oviedo-Roa and M. Cruz-Irisson and O. Navarro},

url = {https://www.sciencedirect.com/science/article/pii/S0167931716302283},

doi = {https://doi.org/10.1016/j.mee.2016.04.026},

issn = {0167-9317},

year  = {2016},

date = {2016-01-01},

journal = {Microelectronic Engineering},

volume = {162},

pages = {110-113},

abstract = {Double perovskites are promising materials for multiple applications on microelectronics, specially on magnetic devices development. Perhaps the most interesting one is the double perovskite Sr2FeMoO6 since its magnetic properties differ from that of other related simple perovskites: SrFeO3 and SrMoO3. In this work the evolution of the electronic properties and the magnetic moment distribution as a function of the Fe/Mo ratio in bulk and a thin slab of Sr2FeMoO6 was studied. The thin slab was constructed keeping free surfaces parallel to the (001) crystalline planes with different thickness and compositions. All calculations were made in the Density Functional Theory scheme in the Generalized Gradient Approximation, using the Perdew-Burke-Ernzerhof functional, as implemented in the DMol3 code. After being geometry optimized, the electronic Density of States and band structure were calculated, as well as the magnetic moment distribution, for each modeled system. Essential results are as follows: for the bulk cases it was found that half-metallic behavior which characterizes the stoichiometric double perovskite changes if the compound becomes molybdenum or iron rich; for the slab is remarkable the induction of magnetic moments, owed to the corresponding to iron atoms, over their neighbor atoms.},

keywords = {Density Functional Theory, electronic properties, Magnetic properties, Perovskites, Thin slabs},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1504/IJNT.2015.067212,

title = {Electronic structure and optical vibrational modes of 3C\textendashSiC nanowires},

author = {Alejandro Trejo and Miguel Ojeda and Jos\'{e} Luis Cuevas and \'{A}lvaro Miranda and Luis A. P\'{e}rez and Miguel Cruz\textendashIrisson},

url = {https://www.inderscienceonline.com/doi/abs/10.1504/IJNT.2015.067212},

doi = {10.1504/IJNT.2015.067212},

year  = {2015},

date = {2015-01-01},

journal = {International Journal of Nanotechnology},

volume = {12},

number = {3-4},

pages = {275-284},

abstract = {The electronic structure and vibrational optical modes of silicon carbide nanowires (SiCNWs) were studied using the first principles density functional theory. The nanowires were modelled along the [111] direction using the supercell technique passivating all the surface dangling bonds with H atoms, OH radicals and a combination of both. Results show that the full OH passivation lowers the band gap energy compared to the full H passivation owing to C\textendashOH surface states. A shift of the highest optical vibrational modes of Si and C to lower frequency values compared to their bulk counterparts was observed in accordance with phonon confinement scheme.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Calvino2014,

title = {DFT Study of the Electronic Structure of Cubic-SiC Nanopores with a C-Terminated Surface},

author = {Marbella Calvino and Alejandro Trejo and Mar\'{i}a Isabel Iturrios and Margarita Clarisaila Cris\'{o}stomo and Eliel Carvajal and M Cruz-Irisson},

url = {https://doi.org/10.1155/2014/471351},

doi = {10.1155/2014/471351},

issn = {1687-4110},

year  = {2014},

date = {2014-06-01},

journal = {Journal of Nanomaterials},

volume = {2014},

pages = {471351},

publisher = {Hindawi Publishing Corporation},

abstract = {A study of the dependence of the electronic structure and energetic stability on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using density functional theory (DFT) and the supercell technique. The pores were modeled by removing atoms in the [001] direction to produce a surface chemistry composed of only carbon atoms (C-phase). Changes in the electronic states of the porous structures were studied by using different passivation schemes: one with hydrogen (H) atoms and the others gradually replacing pairs of H atoms with oxygen (O) atoms, fluorine (F) atoms, and hydroxide (OH) radicals. The results indicate that the band gap behavior of the C-phase pSiC depends on the number of passivation agents (other than H) per supercell. The band gap decreased with an increasing number of F, O, or OH radical groups. Furthermore, the influence of the passivation of the pSiC on its surface relaxation and the differences in such parameters as bond lengths, bond angles, and cell volume are compared between all surfaces. The results indicate the possibility of nanostructure band gap engineering based on SiC via surface passivation agents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TREJO201414,

title = {Theoretical approach to the phonon modes and specific heat of germanium nanowires},

author = {A. Trejo and L. L\'{o}pez-Palacios and R. V\'{a}zquez-Medina and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0921452614003706},

doi = {https://doi.org/10.1016/j.physb.2014.05.005},

issn = {0921-4526},

year  = {2014},

date = {2014-01-01},

journal = {Physica B: Condensed Matter},

volume = {453},

pages = {14-18},

abstract = {The phonon modes and specific heat of Ge nanowires were computed using a first principles density functional theory scheme with a generalized gradient approximation and finite-displacement supercell algorithms. The nanowires were modeled in three different directions: [001], [111], and [110], using the supercell technique. All surface dangling bonds were saturated with Hydrogen atoms. The results show that the specific heat of the GeNWs at room temperature increases as the nanowire diameter decreases, regardless the orientation due to the phonon confinement and surface passivation. Also the phonon confinement effects could be observed since the highest optical phonon modes in the Ge vibration interval shifted to a lower frequency compared to their bulk counterparts.},

note = {Low-Dimensional Semiconductor Structures - A part of the XXII International Material Research Congress (IMRC 2013)},

keywords = {Germanium, Nanowires, Phonons, Specific Heat},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/1.4878289,

title = {Electronic states of lithium passivated germanium nanowires: An ab-initio study},

author = {A Trejo and E. Carvajal and R. V\'{a}zquez-Medina and M. Cruz-Irisson},

url = {https://aip.scitation.org/doi/abs/10.1063/1.4878289},

doi = {10.1063/1.4878289},

year  = {2014},

date = {2014-01-01},

journal = {AIP Conference Proceedings},

volume = {1598},

number = {1},

pages = {114-117},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Trejo2013,

title = {Ab-initio study of anisotropic and chemical surface modifications of $beta$-SiC nanowires},

author = {Alejandro Trejo and Jos\'{e} Luis Cuevas and Fernando Salazar and Eliel Carvajal and Miguel Cruz-Irisson},

url = {https://doi.org/10.1007/s00894-012-1605-y},

doi = {10.1007/s00894-012-1605-y},

issn = {0948-5023},

year  = {2013},

date = {2013-05-01},

journal = {Journal of Molecular Modeling},

volume = {19},

number = {5},

pages = {2043-2048},

abstract = {The electronic band structure and electronic density of states of cubic SiC nanowires (SiCNWs) in the directions [001], [111], and [112] were studied by means of Density Functional Theory (DFT) based on the generalized gradient approximation and the supercell technique. The surface dangling bonds were passivated using hydrogen (H) atoms and OH radicals in order to study the effects of this passivation on the electronic states of the SiCNWs. The calculations show a clear dependence of the electronic properties of the SiCNWs on the quantum confinement, orientation, and chemical passivation of the surface. In general, surface passivation with either H or OH radicals removes the dangling bond states from the band gap, and OH saturation appears to produce a smaller band gap than H passivation. An analysis of the atom-resolved density of states showed that there is substantial charge transfer between the Si and O atoms in the OH-terminated case, which reduces the band gap compared to the H-terminated case, in which charge transfer mainly occurs between the Si and C atoms.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TREJO201310,

title = {Anisotropic effects on the radial breathing mode of silicon nanowires: An ab initio study},

author = {A. Trejo and R. Vazquez-Medina and G. I. Duchen and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S1386947713000404},

doi = {https://doi.org/10.1016/j.physe.2013.02.006},

issn = {1386-9477},

year  = {2013},

date = {2013-01-01},

journal = {Physica E: Low-dimensional Systems and Nanostructures},

volume = {51},

pages = {10-14},

abstract = {The effect of orientation on the frequency of the radial breathing mode (RBM) of silicon nanowires (SiNWs) is investigated by means of the first principles Density Functional Theory approach through the generalized gradient approximation. We compare the RBM frequency of SiNWs orientated in three different directions, [001], [111], and [110]. The RBM is observed by the calculation of the phonon band structure and density of states of the SiNWs through the supercell finite displacement method. Results show that the SiNWs are stable in the three chosen directions since there are no negative frequencies in their phonon band structure and density of states. A clear dependence of the RBM frequency with respect to the growth direction of the nanowires and the phonon confinement was observed as the RBM frequency decreased with an inverse power law in each nanowire direction, with the fitting parameters dependent on the growth direction. These results are important since they could be used as a fingerprint to identify them within different spectroscopy techniques such as Raman.},

note = {IMRC 2012},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{molecules18044776,

title = {Computational Modeling of the Size Effects on the Optical Vibrational Modes of H-Terminated Ge Nanostructures},

author = {Alejandro Trejo and Miguel Cruz-Irisson},

url = {https://www.mdpi.com/1420-3049/18/4/4776},

doi = {10.3390/molecules18044776},

issn = {1420-3049},

year  = {2013},

date = {2013-01-01},

journal = {Molecules},

volume = {18},

number = {4},

pages = {4776--4785},

abstract = {The vibrational dispersion relations of porous germanium (pGe) and germanium nanowires (GeNWs) were calculated using the ab initio density functional perturbation theory with a generalized gradient approximation with norm-conserving pseudopotentials. Both pores and nanowires were modeled using the supercell technique. All of the surface dangling bonds were saturated with hydrogen atoms. To address the difference in the confinement between the pores and the nanowires, we calculated the vibrational density of states of the two materials. The results indicate that there is a slight shift in the highest optical mode of the Ge-Ge vibration interval in all of the nanostructures due to the phonon confinement effects. The GeNWs exhibit a reduced phonon confinement compared with the porous Ge due to the mixed Ge-dihydride vibrational modes around the maximum bulk Ge optical mode of approximately 300 cm−1; however, the general effects of such confinements could still be noticed, such as the shift to lower frequencies of the highest optical mode belonging to the Ge vibrations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Trejo2012,

title = {Computational simulation of the effects of oxygen on the electronic states of hydrogenated 3C-porous SiC},

author = {Alejandro Trejo and Marbella Calvino and Estrella Ramos and Miguel Cruz-Irisson},

url = {https://doi.org/10.1186/1556-276X-7-471},

doi = {10.1186/1556-276X-7-471},

issn = {1556-276X},

year  = {2012},

date = {2012-08-22},

journal = {Nanoscale Research Letters},

volume = {7},

number = {1},

pages = {471},

abstract = {A computational study of the dependence of the electronic band structure and density of states on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using ab initio density functional theory and the supercell method. The effects of the porosity and the surface chemistry composition on the energetic stability of pSiC were also investigated. The porous structures were modeled by removing atoms in the [001] direction to produce two different surface chemistries: one fully composed of silicon atoms and one composed of only carbon atoms. The changes in the electronic states of the porous structures as a function of the oxygen (O) content at the surface were studied. Specifically, the oxygen content was increased by replacing pairs of hydrogen (H) atoms on the pore surface with O atoms attached to the surface via either a double bond (Xthinspace=thinspaceO) or a bridge bond (X-O-X, Xthinspace=thinspaceSi or C). The calculations show that for the fully H-passivated surfaces, the forbidden energy band is larger for the C-rich phase than for the Si-rich phase. For the partially oxygenated Si-rich surfaces, the band gap behavior depends on the O bond type. The energy gap increases as the number of O atoms increases in the supercell if the O atoms are bridge-bonded, whereas the band gap energy does not exhibit a clear trend if O is double-bonded to the surface. In all cases, the gradual oxygenation decreases the band gap of the C-rich surface due to the presence of trap-like states.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{CALVINO20121482,

title = {A Density Functional Theory study of the chemical surface modification of β-SiC nanopores},

author = {M. Calvino and A. Trejo and J. L. Cuevas and E. Carvajal and G. I. Duch\'{e}n and M. Cruz-Irisson},

url = {https://www.sciencedirect.com/science/article/pii/S0921510712000918},

doi = {https://doi.org/10.1016/j.mseb.2012.02.009},

issn = {0921-5107},

year  = {2012},

date = {2012-01-01},

journal = {Materials Science and Engineering: B},

volume = {177},

number = {16},

pages = {1482-1486},

abstract = {The dependence of the electronic band structure and density of states on the chemical surface passivation of cubic porous silicon carbide (PSiC) is investigated by means of the ab-initio Density Functional Theory and the supercell method in which pores with different sizes and morphologies were created. The porous structures were modeled by removing atoms in the [001] direction producing two different surface chemistries; one with both Silicon (Si) and Carbon (C) atoms and the other with only Si or C atoms. The changes in the electronic band gap due to a Si-rich and C-rich phase in the porous surfaces are studied with two kind of surface passivation, one with hydrogen atoms and other with a combination between hydrogen and oxygen atoms. The calculations show that for the hydrogenated case, the band gap is larger for the C-rich than for the Si-rich case. For the partial oxygenation the tendency is contrary, by decreasing and increasing the band gap for the C-rich and Si-rich configuration, respectively, according to the percentage of oxygen in the pore surface.},

note = {Advances in Semiconducting Materials},

keywords = {Density Functional Theory, Porous silicon carbide, Surface passivation},

pubstate = {published},

tppubtype = {article}

}