LASER-ASSISTED VAPOR-PHASE EPITAXY OF ZNSE ON GAAS

Epitaxial layers of ZnSe have been grown on (100) GaAs by photoassisted vapor-phase epitaxy with the use of a He-Cd laser (power P similar or equal to 1 mW/cm(2) h nu = 2.807 eV) from powder sources in a flow of purified hydrogen. The rate of growth of the films was thereby decreased. A study of-the photoluminescence spectra at T = 4.5 K of the ZnSe films grown in this way reveals an increase in the intensity of the free-exciton emission compared with samples prepared under similar growth conditions, but without the assisting illumination. The crystalline perfection of the samples prepared by photoassisted vapor phase epitaxy are found also to be superior, as verified by x-ray studies and an electron-microscope analysis of the surface morphology of the films. The observed effects cannot be explained by thermal desorption. It is proposed that they are connected with photoactivated processes of adsorption and desorption through a change in the surface mobility of the adsorbed atoms. (C) 1995 American Institute of Physics.