DENSITY OF DEFECTS IN THE SURFACE PARTS OF HYDROGENATED AMORPHOUS-SILICON FILMS

The results of an experimental study of the density of defects in the form of dangling Si-Si bonds in the skin ( 15-100 nm) layers of a-Si:H films formed by the pseudodoping method, i.e., characterized by epsil on(F) = var without special doping (where epsilon(F) is the Fermi leve l in the bulk of a film) are presented. The investigation was carried out by the methods of ultrasoft x-ray emission spectroscopy and consta nt photocurrent. Quantitative information was obtained on the distribu tion of the density of dangling bonds as a function of the depth of pr obing of a film and of the position of epsilon(F) in the bulk of the f ilm. The value of the Urbach parameter was determined for the skin lay ers of the films.