PHOTOREFLECTANCE STUDY OF CUALSE2 HETEROEPITAXIAL LAYERS

Photoreflectance (PR) spectra have been measured on the CuAlSe2 epitaxial layers grown on GaAs(100), GaAs(111)A and GaP(100) substrates by means of the metal organic chemical vapor deposition technique. The PR spectra showed strong dependence on the substrate, reflecting the orientation of the epitaxial layer. The results have been well explained from the polarization selection rule with the aid of X-ray measurements. Stress in the epitaxial layer is discussed in terms of the crystal field splitting of the valence bands.