Peculiarities of the electronic structure and phase composition of amorphous (SiO2) x (a-Si: H) x–1 composite films according to X-ray spectroscopy data

Abstract

Amorphous (SiO2) x (a-Si: H) x–1 composite films have been deposited from plasma of dc magnetron discharge switched on and off for variable periods of time. The electronic structure and phase composition of obtained films were studied by methods of ultrasoft X-ray emission spectroscopy (USXES) and X-ray absorption near edge structure (XANES) spectroscopy using synchrotron radiation. The results of a qualitative and semiquantitative analysis of the phase composition of films with the use of a special method of computer simulation showed that the content of amorphous a-Si: H clusters in SiO2 matrix can be varied within wide limits by changing the period of dc magnetron discharge switching. It is established that the formation of a large number of silicon nanoclusters in the (SiO2) x (a-Si: H) x–1 composite film leads to the appearance of anomalies in the XANES spectra, which are related to the scattering of synchrotron radiation on nanoclusters with dimensions comparable to the radiation wavelength near the X-ray absorption edge of silicon.