Hydrogen can be trapped in the bulk materials in four forms： interstitial molecular H2, interstitial atom H, O-H＋（2Si=O-H）＋, Si-H-（4O SiH）- to affect the electronic and optical properties of amorphous silica. T...Hydrogen can be trapped in the bulk materials in four forms： interstitial molecular H2, interstitial atom H, O-H＋（2Si=O-H）＋, Si-H-（4O SiH）- to affect the electronic and optical properties of amorphous silica. Therefore, the electronic and optical properties of defect-free and hydrogen defects in amorphous silica were performed within the scheme of density functional theory. Initially, the negative charged states hydrogen defects introduced new defect level between the valence band top and conduction band bottom. However, the neutral and positive charged state hydrogen defects made both the valence band and conduction band transfer to the lower energy. Sub- sequently, the optical properties such as absorption spectra, conductivity and loss functions were analyzed. It is in- dicated that the negative hydrogen defects caused the absorption peak ranging from 0 to 2.0 eV while the positive states produced absorption peaks at lower energy and two strong absorption peaks arose at 6.9 and 9.0 eV. However, the neutral hydrogen defects just improved the intensity of absorption spectrum. This may give insights into understanding the mechanism of laser-induced damage for optical materials.展开更多
基金Project supported by the Science and Technology of Hubei Provincial Department of Education(No.B2017098)
文摘Hydrogen can be trapped in the bulk materials in four forms： interstitial molecular H2, interstitial atom H, O-H＋（2Si=O-H）＋, Si-H-（4O SiH）- to affect the electronic and optical properties of amorphous silica. Therefore, the electronic and optical properties of defect-free and hydrogen defects in amorphous silica were performed within the scheme of density functional theory. Initially, the negative charged states hydrogen defects introduced new defect level between the valence band top and conduction band bottom. However, the neutral and positive charged state hydrogen defects made both the valence band and conduction band transfer to the lower energy. Sub- sequently, the optical properties such as absorption spectra, conductivity and loss functions were analyzed. It is in- dicated that the negative hydrogen defects caused the absorption peak ranging from 0 to 2.0 eV while the positive states produced absorption peaks at lower energy and two strong absorption peaks arose at 6.9 and 9.0 eV. However, the neutral hydrogen defects just improved the intensity of absorption spectrum. This may give insights into understanding the mechanism of laser-induced damage for optical materials.
