TY - JOUR
T1 - Interconnection effects on the electronic and optical properties of Ge nanostructures
T2 - A semi-empirical approach
AU - Miranda, A.
AU - Trejo, A.
AU - Canadell, E.
AU - Rurali, R.
AU - Cruz-Irisson, M.
N1 - Funding Information:
This work was partially supported by Postdoctoral Abroad—Consejo Nacional de Ciencia y Tecnología, Multidisciplinary Project SIP: 2012-1439 of Instituto Politécnico Nacional. The supercomputing facilities of the ICMAB are fully acknowledged.
PY - 2012/4
Y1 - 2012/4
N2 - A supercell model is applied to a semi-empirical sp3s tight-binding (TB) approach to calculate the electronic band gap and imaginary part of the dielectric function of two Ge nanostructures - ordered arrays of pores and stand-alone nanowires - and one example of their interconnections. The pores are modeled by removing columns of Ge atoms in the [0 0 1] direction. The results of the variation band gap are compared with those obtained by TB-sp 3, TB- sp3d5s, density functional theory (DFT), and experimental data. The imaginary part of the dielectric function is calculated by including both intra-atomic and inter-atomic dipole matrices using (for both) the interconnected and free standing (chessboard-like) models for the Ge skeleton. The calculation shows that although the intra-atomic matrix elements are small in magnitude a quantitative treatment of the optical absorption spectrum of Ge nanostructures may not be possible without the inclusion of these matrix elements. Finally, the calculations confirm that also ordered porous germanium (PGe) show a clear quantum confinement signature, even though the wave functions could in principle behave like delocalized Bloch states.
AB - A supercell model is applied to a semi-empirical sp3s tight-binding (TB) approach to calculate the electronic band gap and imaginary part of the dielectric function of two Ge nanostructures - ordered arrays of pores and stand-alone nanowires - and one example of their interconnections. The pores are modeled by removing columns of Ge atoms in the [0 0 1] direction. The results of the variation band gap are compared with those obtained by TB-sp 3, TB- sp3d5s, density functional theory (DFT), and experimental data. The imaginary part of the dielectric function is calculated by including both intra-atomic and inter-atomic dipole matrices using (for both) the interconnected and free standing (chessboard-like) models for the Ge skeleton. The calculation shows that although the intra-atomic matrix elements are small in magnitude a quantitative treatment of the optical absorption spectrum of Ge nanostructures may not be possible without the inclusion of these matrix elements. Finally, the calculations confirm that also ordered porous germanium (PGe) show a clear quantum confinement signature, even though the wave functions could in principle behave like delocalized Bloch states.
UR - http://www.scopus.com/inward/record.url?scp=84861736283&partnerID=8YFLogxK
U2 - 10.1016/j.physe.2012.01.017
DO - 10.1016/j.physe.2012.01.017
M3 - Artículo
SN - 1386-9477
VL - 44
SP - 1230
EP - 1235
JO - Physica E: Low-Dimensional Systems and Nanostructures
JF - Physica E: Low-Dimensional Systems and Nanostructures
IS - 7-8
ER -