PHOTOCONDUCTIVITY OF AMORPHOUS HYDROGENATED CARBON-FILMS PREPARED BY PLASMA CVD OF ACETYLENE

Amorphous hydrogenated carbon (a-C:H) films were deposited (at room te mperature) by plasma CVD of acetylene onto glass substrates with subst rate bias (V-B) varying within 0 to - 400 V. Films deposited at \V-B\ greater than or equal to 200 V showed significant photoconductivity. T he photoconductivity of the films was measured under different illumin ation level (0-100 mW/cm(2)). Hopping at the shallow localized states was the predominant mode of electron transport process in these films. Photo-induced conduction process in the amorphous material in the tem perature region 80 < T < 300 K could be explained by the multi-trappin g model of photo excited carriers. Copyright (C) 1996 Elsevier Science Ltd.