Thickness dependence of double crystal rocking curves and photoluminescence in ZnS epilayers grown on GaAs 100/and GaP 100/

High quality ZnSrGaAs and ZnSrGaP epilayers are grown by hot wall epitaxy. The full width at half maximum FWHM.of the double crystal rocking curves DCRC.and photoluminescence PL.are measured to investigate the crystalline quality of ZnSrGaAs and ZnSrGaP epilayers. The best value of the FWHM of the DCRC for ZnSrGaAs epilayers at 3.8 mm thickness is 373 arcsec, and for ZnSrGaP epilayers at 4.7 mm thickness of 173 arcsec. The PL spectra of ZnSrGaAs and ZnSrGaP epilayers reveal very strong near-edge emission peaks, no deep level peaks and self-activated peaks. The band gap energy Eg for ZnS epilayer is measured at 3.729 eV at the room temperature. The tensile strain due to the lattice mismatch and the thermal expansion coefficient difference between ZnS epilayer and GaAs or GaP.substrate is existed in ZnS epilayers. In this study, the thickness dependence of DCRC and PL for ZnS epilayers is analyzed taking into account the tensile strain. q1999 Elsevier Science B.V. All rights reserved