Optical and Electrical Properties of Hydrogenated Amorphous Silicon Carbide

Abstract

Abstract Hydrogenated amorphous silicon carbide thin films are prepared by RF sputtering. The amorphous structure of the hydrogenated films and their hydrogen content are ascertained by Raman and infrared spectroscopy. The principal reststrahlen band does not shift in frequency but appears to sharpen with the increase in hydrogen concentration. The hydrogen content is estimated by the integrated band intensities of silicon‐hydrogen and carbon‐hydrogen and carbon‐hydrogen modes in the infrared absorption. The hydrogen content has a dominant effect on the optical pseudo‐gap and the dc conductivity of the amorphous films. A blue shift is observed in the absorption edge with increasing hydrogen content. The dc conductivity of the films is studied in the temperature range of 120 to 400 K. High temperature data yield an activation energy gap which increases significantly with hydrogen content, while the low temperature conductivity is explained by hopping between localized states.