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Theoretical Study of the Gradual Chemical Transition at the SiSiO 2 Interface. II. Electronic Density of States Calculations
Author(s) -
Hübneb K.,
Stern A.,
Klinkenberg E.D.
Publication year - 1986
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221360124
Subject(s) - dangling bond , bethe lattice , condensed matter physics , lattice (music) , chemical bond , cluster (spacecraft) , materials science , semiconductor , density of states , valence (chemistry) , electronic structure , chemistry , silicon , physics , metallurgy , organic chemistry , computer science , acoustics , ising model , programming language , optoelectronics
Calculations of the electronic density of states at the Si‐SiO 2 interface performed with the help of the cluster‐Bethe‐lattice method are presented. A cluster is constructed, which realizes the semiconductor‐insulator transition between a Bethe lattice of Si atoms and an SiO 2 Bethe lattice within three atomic SiO x layers with average x values of 0.33, 1.17, and 1.67. The resulting densities of states are compared with corresponding results for bulk SiO x and the static effective charges of all the cluster atoms are calculated. It is shown that an intermediate‐range order (Si‐Si chains and rings) strongly influences the position of the valence‐band edge and, therefore, the variation of the width of the gap in dependence on the chemical composition x across the Si‐SiO 2 inter‐region. The defect levels resulting from dangling bonds of Si atoms with different backbond configurations and from a peroxy bridge and a peroxy radical are investigated. An influence of structural percolation effects on the dangling‐bond levels is shown. Further microscopic origins of interface states are discussed.