Molecular beam epitaxial growth of CuGaSe₂ films

Cu-Ga-Se films of various compositions were prepared by MBE technique. The films were examined by reflection high energy electron diffraction, electron probe for micro analysis, X-ray diffraction and photoluminescence. The valence stoichiometry of the films is fulfilled at unity molecularity, showing that CuGaSe₂ is possible to be grown by MBE. The stoichiometry is almost conserved in a wide range of molecularity of the films. The films have chalcopyrite structure over a remarkably wide range of Cu-rich composition. They grow epitaxially on [001] oriented GaAs substrates with the c-axis perpendicular to the substrate surface. The low temperature photoluminescence from epitaxially grown films of nearly stoichiometric and Cu-rich composition show sharp emissions peaked at 1.71eV attributable to exciton recombination, indicating high quality of the films.