2022
Cuevas, J. L.; Ojeda, M.; Calvino, M.; Trejo, A.; Salazar, F.; Miranda, A.; Perez, L. A.; Cruz-Irisson, M.
Theoretical approach to the phonon modes of GaSb nanowires Artículo de revista
En: Physica E: Low-dimensional Systems and Nanostructures, vol. 143, pp. 115372, 2022, ISSN: 1386-9477.
Resumen | Enlaces | BibTeX | Etiquetas: DFT, Gallium Antimonide, Nanowires, Phonons
@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}
}
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.
2018
Santiago, Francisco; Miranda, Álvaro; Trejo, Alejandro; Salazar, Fernando; Carvajal, Eliel; Cruz-Irisson, Miguel; Pérez, Luis A.
Quantum confinement effects on the harmful-gas-sensing properties of silicon nanowires Artículo de revista
En: International Journal of Quantum Chemistry, vol. 118, no 20, pp. e25713, 2018.
Resumen | Enlaces | BibTeX | Etiquetas: Density Functional Theory, Nanowires, Sensors, silicon, toxic gases
@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}
}
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.
2014
Trejo, A.; López-Palacios, L.; Vázquez-Medina, R.; Cruz-Irisson, M.
Theoretical approach to the phonon modes and specific heat of germanium nanowires Artículo de revista
En: Physica B: Condensed Matter, vol. 453, pp. 14-18, 2014, ISSN: 0921-4526, (Low-Dimensional Semiconductor Structures - A part of the XXII International Material Research Congress (IMRC 2013)).
Resumen | Enlaces | BibTeX | Etiquetas: Germanium, Nanowires, Phonons, Specific Heat
@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}
}
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.
2012
Cuevas, J. L.; Trejo, A.; Calvino, M.; Carvajal, E.; Cruz-Irisson, M.
Ab-initio modeling of oxygen on the surface passivation of 3CSiC nanostructures Artículo de revista
En: Applied Surface Science, vol. 258, no 21, pp. 8360-8365, 2012, ISSN: 0169-4332, (VII International Workshop on Semiconductor Surface Passivation, KRAKÓW, POLAND, September 11 - 15, 2011).
Resumen | Enlaces | BibTeX | Etiquetas: Density Functional Theory, Nanowires, Porous semiconductors, Silicon carbide
@article{CUEVAS20128360,
title = {Ab-initio modeling of oxygen on the surface passivation of 3CSiC nanostructures},
author = {J. L. Cuevas and A. Trejo and M. Calvino and E. Carvajal and M. Cruz-Irisson},
url = {https://www.sciencedirect.com/science/article/pii/S0169433212006289},
doi = {https://doi.org/10.1016/j.apsusc.2012.03.175},
issn = {0169-4332},
year = {2012},
date = {2012-01-01},
journal = {Applied Surface Science},
volume = {258},
number = {21},
pages = {8360-8365},
abstract = {In this work the effect of OH on the electronic states of H-passivated 3CSiC nanostructures, was studied by means of Density Functional Theory. We compare the electronic band structure for a [111]-oriented nanowire with total H, OH passivation and a combination of both. Also the electronic states of a porous silicon carbide case (PSiC) a C-rich pore surface in which the dangling bonds on the surface are saturated with H and OH was studied. The calculations show that the surface replacement of H with OH radicals is always energetically favorable and more stable. In all cases the OH passivation produced a similar effect than the H passivation, with electronic band gap of lower energy value than the H-terminated phase. When the OH groups are attached to C atoms, the band gap feature is changed from direct to indirect. The results indicate the possibility of band gap engineering on SiC nanostructures through the surface passivation species.},
note = {VII International Workshop on Semiconductor Surface Passivation, KRAK\'{O}W, POLAND, September 11 - 15, 2011},
keywords = {Density Functional Theory, Nanowires, Porous semiconductors, Silicon carbide},
pubstate = {published},
tppubtype = {article}
}
In this work the effect of OH on the electronic states of H-passivated 3CSiC nanostructures, was studied by means of Density Functional Theory. We compare the electronic band structure for a [111]-oriented nanowire with total H, OH passivation and a combination of both. Also the electronic states of a porous silicon carbide case (PSiC) a C-rich pore surface in which the dangling bonds on the surface are saturated with H and OH was studied. The calculations show that the surface replacement of H with OH radicals is always energetically favorable and more stable. In all cases the OH passivation produced a similar effect than the H passivation, with electronic band gap of lower energy value than the H-terminated phase. When the OH groups are attached to C atoms, the band gap feature is changed from direct to indirect. The results indicate the possibility of band gap engineering on SiC nanostructures through the surface passivation species.
Trejo, A.; Miranda, A.; Rivera, L. Niño; Díaz-Méndez, A.; Cruz-Irisson, M.
Phonon optical modes and electronic properties in diamond nanowires Artículo de revista
En: Microelectronic Engineering, vol. 90, pp. 92-95, 2012, ISSN: 0167-9317, (Micro&Nano 2010).
Resumen | Enlaces | BibTeX | Etiquetas: Diamond, Nanowires, Phonons, Raman scattering, Tight-binding
@article{TREJO201292,
title = {Phonon optical modes and electronic properties in diamond nanowires},
author = {A. Trejo and A. Miranda and L. Ni\~{n}o Rivera and A. D\'{i}az-M\'{e}ndez and M. Cruz-Irisson},
url = {https://www.sciencedirect.com/science/article/pii/S016793171100476X},
doi = {https://doi.org/10.1016/j.mee.2011.04.052},
issn = {0167-9317},
year = {2012},
date = {2012-01-01},
journal = {Microelectronic Engineering},
volume = {90},
pages = {92-95},
abstract = {A local bond-polarization model based on the displacement\textendashdisplacement Green’s function and the Born potential are applied to study the confined optical phonons and Raman scattering of diamond nanowires (DNWs). Also, the electronic band structure of DNWs are investigated by means of a semi-empirical tight-binding approach and compared with density functional theory within local density approximation. The supercell technique is applied to model DNWs along [001] direction preserving the crystalline diamond atomic structure. The results of both phonons and electrons show a clear quantum confinement signature. Moreover, the highest energy Raman peak shows a shift towards low frequencies respect to the bulk crystalline diamond, in agreement with experimental data.},
note = {Micro\&Nano 2010},
keywords = {Diamond, Nanowires, Phonons, Raman scattering, Tight-binding},
pubstate = {published},
tppubtype = {article}
}
A local bond-polarization model based on the displacement–displacement Green’s function and the Born potential are applied to study the confined optical phonons and Raman scattering of diamond nanowires (DNWs). Also, the electronic band structure of DNWs are investigated by means of a semi-empirical tight-binding approach and compared with density functional theory within local density approximation. The supercell technique is applied to model DNWs along [001] direction preserving the crystalline diamond atomic structure. The results of both phonons and electrons show a clear quantum confinement signature. Moreover, the highest energy Raman peak shows a shift towards low frequencies respect to the bulk crystalline diamond, in agreement with experimental data.
2010
Miranda, A.; Serrano, F. A.; Vázquez-Medina, R.; Cruz-Irisson, M.
Hydrogen surface passivation of Si and Ge nanowires: A semiempirical approach Artículo de revista
En: International Journal of Quantum Chemistry, vol. 110, no 13, pp. 2448-2454, 2010.
Resumen | Enlaces | BibTeX | Etiquetas: Germanium, Nanowires, optical properties, silicon, Tight-binding
@article{https://doi.org/10.1002/qua.22753,
title = {Hydrogen surface passivation of Si and Ge nanowires: A semiempirical approach},
author = {A. Miranda and F. A. Serrano and R. V\'{a}zquez-Medina and M. Cruz-Irisson},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/qua.22753},
doi = {https://doi.org/10.1002/qua.22753},
year = {2010},
date = {2010-01-01},
urldate = {2010-01-01},
journal = {International Journal of Quantum Chemistry},
volume = {110},
number = {13},
pages = {2448-2454},
abstract = {Abstract A semiempirical nearest-neighbor tight-binding approach, that reproduces the indirect band gaps of elemental semiconductors, has been applied to study the electronic and optical properties of Si and Ge nanowires (NWs). The calculations show that Si-NWs keep the indirect bandgap whereas Ge-NWs changes into the direct bandgap when the wire cross section becomes smaller. Also, the band gap enhancement of Si-NWs showing to quantum confinement effects is generally larger than that of similar-sized Ge-NWs, confirming the larger quantum confinement effects in Si than in Ge when they are confined in two dimensions. Finally, the dependence of the imaginary part of the dielectric function on the quantum confinement within two different schemes: intra-atomic and interatomic optical matrix elements are applied. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2448\textendash2454, 2010},
keywords = {Germanium, Nanowires, optical properties, silicon, Tight-binding},
pubstate = {published},
tppubtype = {article}
}
Abstract A semiempirical nearest-neighbor tight-binding approach, that reproduces the indirect band gaps of elemental semiconductors, has been applied to study the electronic and optical properties of Si and Ge nanowires (NWs). The calculations show that Si-NWs keep the indirect bandgap whereas Ge-NWs changes into the direct bandgap when the wire cross section becomes smaller. Also, the band gap enhancement of Si-NWs showing to quantum confinement effects is generally larger than that of similar-sized Ge-NWs, confirming the larger quantum confinement effects in Si than in Ge when they are confined in two dimensions. Finally, the dependence of the imaginary part of the dielectric function on the quantum confinement within two different schemes: intra-atomic and interatomic optical matrix elements are applied. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2448–2454, 2010
2009
Miranda, A.; Cuevas, J. L.; Ramos, A. E.; Cruz-Irisson, M.
Quantum confinement effects on electronic properties of hydrogenated 3C–SiC nanowires Artículo de revista
En: Microelectronics Journal, vol. 40, no 4, pp. 796-798, 2009, ISSN: 1879-2391, (European Nano Systems (ENS 2007) International Conference on Superlattices, Nanostructures and Nanodevices (ICSNN 2008)).
Resumen | Enlaces | BibTeX | Etiquetas: Density Functional Theory, Nanowires, Silicon carbide, Tight-binding
@article{MIRANDA2009796,
title = {Quantum confinement effects on electronic properties of hydrogenated 3C\textendashSiC nanowires},
author = {A. Miranda and J. L. Cuevas and A. E. Ramos and M. Cruz-Irisson},
url = {https://www.sciencedirect.com/science/article/pii/S0026269208005375},
doi = {https://doi.org/10.1016/j.mejo.2008.11.034},
issn = {1879-2391},
year = {2009},
date = {2009-01-01},
urldate = {2009-01-01},
journal = {Microelectronics Journal},
volume = {40},
number = {4},
pages = {796-798},
abstract = {In this work, the effect of the morphology on the electronic band structure and density of states of hydrogenated silicon carbide nanowires is studied by using a semiempirical sp3s* tight-binding (TB) approach applied to the supercell model, where the Si- and C-dangling bonds are passivated by hydrogen atoms. The TB results are compared with those of ab-initio density functional theory within the local density approximation, showing that this method gives systematically larger energy gaps than the TB one. As expected, hydrogen saturation induces a broadening of the band gap energy due to quantum confinement effect.},
note = {European Nano Systems (ENS 2007) International Conference on Superlattices, Nanostructures and Nanodevices (ICSNN 2008)},
keywords = {Density Functional Theory, Nanowires, Silicon carbide, Tight-binding},
pubstate = {published},
tppubtype = {article}
}
In this work, the effect of the morphology on the electronic band structure and density of states of hydrogenated silicon carbide nanowires is studied by using a semiempirical sp3s* tight-binding (TB) approach applied to the supercell model, where the Si- and C-dangling bonds are passivated by hydrogen atoms. The TB results are compared with those of ab-initio density functional theory within the local density approximation, showing that this method gives systematically larger energy gaps than the TB one. As expected, hydrogen saturation induces a broadening of the band gap energy due to quantum confinement effect.
