Second harmonic generation in hydrogenated amorphous silicon

Abstract

The first application of the second harmonic generation (SHG) technique to investigate the structure of $a\ensuremath{-}\mathrm{S}\mathrm{i}:\mathrm{H}$ films is reported. Dependence of SHG on the type of substrate material and the temperature during deposition has been observed. The origin of SHG is discussed. A stress model is proposed to explain the experimental results. It is suggested that the second harmonic is generated in a strained layer close to the substrate.