High quality CuInSe2 films grown on pseudo-lattice-matched substrates by molecular beam epitaxy

Abstract

CuInSe₂ films have been grown by molecular beam epitaxy on pseudo‐lattice‐matched substrates that consist of a 1‐μm‐thick In_0.29Ga_0.71As layer grown on a linearly composition‐graded In_xGa_1−xAs buffer (0≤x≤0.29) grown in turn on GaAs (001). The properties of these films have been compared with those of the films grown directly on GaAs (001). High resolution x‐ray diffraction analysis on CuInSe₂ grown on pseudo‐lattice‐matched substrates indicated substantial reduction on residual strain in the CuInSe₂ films. A photoluminescence spectrum dominated by sharp free exciton emissions has been observed for the first time from CuInSe₂ films indicative of significant improvement in crystalline quality and substantial reduction in the point defect density.