Showing papers by "M. T. S. Nair published in 2003"
TL;DR: In this paper, a chemically deposited CuS thin film on which a thin film of bismuth was thermally evaporated is shown to have p-type conductivity of 0.03 Ω−1 cm−1 and is photoconductive.
Abstract: Semiconducting thin films of Cu3BiS3, with structure and composition corresponding to that of the mineral wittichenite, have been prepared by heating at 300 °C in nitrogen atmosphere a chemically deposited CuS thin film on which a thin film of bismuth was thermally evaporated. This follows a stoichiometric reaction: CuS (300 nm) + Bi (103 nm) giving Cu3BiS3 (397 nm). The optical absorption coefficient in the visible region for this material is >105 cm−1. This optical absorption is classified as due to direct (forbidden) transitions, with an optical bandgap of 1.2 ± 0.1 eV. Weak optical absorption related to an indirect (forbidden) gap of 0.65 eV is also identified. The Cu3BiS3 thin film has a p-type conductivity of 0.03 Ω−1 cm−1 and is photoconductive. The mobility-lifetime product of photogenerated carriers is estimated to be 10−6 cm2 V−1.
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