Hydrogen bonding and void microstructure of a-Ge:H films

Abstract

This article reports on the microvoid structure of hydrogenated amorphous germanium films, as determined from small angle x-ray scattering data and infrared transmission spectroscopy, and its dependence on three deposition parameters, namely, the substrate temperature, the particle bombardment during film growth, and the partial pressure of hydrogen in the deposition chamber. The structure of the alloys depends on the first two deposition parameters and not on the partial pressure of hydrogen. The dependence of the optical gap on hydrogenation and microstructure is established for a-Ge:H films for a wide range of deposition conditions.