Nature of Localized States in Hydrogenated Si–Based Amorphous Semiconductor Films Elucidated from LESR and CPM

Abstract
Measurements of low energy absorption by the constant photocurrent method, ESR and light-induced ESR were carried out for a-Si:H, a-Si1-x C x :H, a-Si1-x O x :H and a-Si1-x N x :H films as a function of the film thickness. As a result, both the surface density of dangling bonds in the disordered surface layer and the density of dangling bonds in the bulk region were obtained by discriminating between neutral and charged dangling bonds. It is found that many charged defects are present even in high-purity a-Si:H films and their density increases with the addition of O and N. We attribute these charged defects to Si3 -+N4 + in a-Si1-x N x :H, in contrast to the model of Robertson and Powell, and to Si3 -+O3 - in a-Si1-x O x :H.

This publication has 17 references indexed in Scilit: