Properties of a-Si 1 −x C x:H thin films deposited from the organosilane Triethylsilane

Abstract

We deposited carbon-rich a-Si 1 −x C x :H thin films from the liquid organosilane source Triethylsilane (C 2 H 5) 3-Si–H (TrES) in a PECVD process at 13.56 MHz. These films generally show a photoluminescence in the visible spectral range when excited with ultraviolet light. By increasing the substrate temperature from room temperature up to 300°C we can red shift the PL peak energy and also the optical Tauc gap. Furthermore, an increase in the film density and correspondingly in the refractive index is observed. FTIR measurements show that these films have a polymer–like character for all temperatures under investigation. The hydrogen concentration is calculated from the stretching modes of CH n and SiH n groups, respectively, and is shown to decrease with substrate temperature. We also show that the amount of hydrogen bonded to carbon decreases with respect to that bonded to silicon with substrate temperature.