Optimum Growth Conditions of CdS Thin Films Grown on GaAs (111) B by MBE

Abstract

Optimum growth conditions of CdS thin films depositted on GaAs (111) B substrate by MBE were investigated. The films were characterized by full width at half maximum (FWHM) of X-ray diffraction (XRD) rocking curve, photoluminescence (PL), and surface morphology by scanning electron microscopy. The FWHM became minimum when the film was grown under the following conditions : The substrate temperature of 280°C, the ratio of molecular beam intensity of S to that of Cd about 1/1.5 and the interruption period of Cd supply for about 0.1 second. Although buffer layer depositted at 150°C for 15 seconds did not seem to affect the FWHM of the film, PL spectra indicated that the film with the buffer layer had better quality than that without the buffer layer. The roughness of the film surface was found to decrease by insertion of the buffer layer.