Epitaxial layers of CuGaTe2 on GaAs

CuGaTe2 thin films with thicknesses in the range from 0.1 to 0.2 μm were deposited onto semi-insulating (111) A-oriented GaAs substrates by flash evaporation under controlled growth conditions. Epitaxial growth begins at a substrate temperature of Tsub(sub) = 695 K. In the range Tsub(sub) = 695 ... 820 K the films have the chalcopyrite structure, at Tsub(sub) = 820 to 840 K a second phase was observed besides the chalcopyrite phase. At Tsub(sub) > 840 K the films become polycrystalline. All epitaxial films were p-type conducting and showed an increase of the hole concentration with rising substrate temperature. The measured mobilities indicate to the presence of a high concentration of neutral impurities or defects. (author)