Optical properties of CdS layers grown by MOVPE on (211) B and (100) GaAs
CdS layers were grown by MOVPE on (100) GaAs and (211)B GaAs substrates. The last substrate orientation yields homogeneous wurtzite CdS layers with sharply defined free excitonic structures seen in optical reflectivity and photoluminescence. Free exciton luminescence dominates the spectrum at T >50 K. Structural studies indicate that the layers grown on (100) GaAs substrates are a mixture of hexagonal and cubic CdS phases spatially arranged in a quasi-periodic fashion. The luminescence spectrum reflects this situation.