Growth of CdTe Thin Films on Polar and Nonpolar Semiconductor Substrates by Metalorganic Chemical Vapor Deposition.

ABSTRACTElectron diffraction and high resolution electron microscopy (HREM) have been used to investigate the origin of multiple orientation-relationships and defect structure of CdTe thin films grown on (100) GaAs and Si substrates by metal- organic chemical vapor deposition (MOCVD). It has been determined that growth at 370°C with pre-exposure of the GaAs surface to Te following oxide desorption treatment at 600°C resulted in non-parallel epitaxy ((111)CdTe // (100)GaAs), while growth at 300°C following oxide desorption at 500°C with no exposure to Te resulted in parallel epitaxy ((100)CdTe // (100)GaAs). Both epitaxial orientation-relationships were observed on the same substrate for growth at 300°C temperature after 600°C oxide desorption treatment, but with no pre-exposure of the GaAs surface to Te. Preliminary results of growth of CdTe on Si are also reported.