Structural and electrical properties of CuGaSe₂ thin films on GaAs substrates

CuGaSe 2 thin films with thicknesses in the range of 0.1 μm were deposited onto semiinsulating (111) A‐oriented GaAs substrates by flash evaporation under controlled growth conditions. Epitaxial growth begins at a substrate temperature of T sub = 835 K. Besides the chalcopyrite phase a hexagonal modification was observed in the range T sub = 835 to 855 K. At T sub ≧ 860 K the films have sphalerite structure. All epitaxial films were p‐type conducting. Two acceptor levels with ionization energies of about 150 meV and 550 meV, respectively, were obtained from an analysis of electrical and photoluminescence measurements.