E. Degoli et al., Symmetry and passivation dependence of the optical properties of nanocrystalline silicon structures, MAT SCI E B, 69, 2000, pp. 444-448
The electronic and optical properties of Si-based quantum wells (QW's) are
studied ab initio by means of the linear-muffin-tin-orbital (LMTO) method i
n order to investigate their dependence on the symmetry of the lattice and
on the passivating species that saturates the Si dangling bonds. We find th
at the symmetry of the lattice changes the nature of the gap that is indire
ct in the Si-H(111) saturated QW's and becomes direct in the Si-H(001) satu
rated QW's. The saturating species play instead an important role in the fo
rmation of interface states that can occupy or leave free the band gap so i
mproving or making worse the optical properties of the material. Studying t
he Si-SiO2(001) superlattice we found that oxygen related defects play an i
mportant role in the determination of the optoelectronic properties of the
material. (C) 2000 Elsevier Science S.A. All rights reserved.