The diffusion of Cu in homo-epitaxial material was investigated by using low-temperature photoluminescence spectroscopy and secondary ion mass spectroscopy. It was found that, although Cu normally diffused easily in this material, the Cu in a ZnSe substrate did not diffuse into the homo-epitaxial layer when the substrate was heated under Se-beam irradiation before growth. The Cu-related emissions, such as I1deep and Cu-green, disappeared from the photoluminescence spectrum of a homo-epitaxial layer which was grown onto Se-beam irradiated substrates. The suppressed Cu diffusion could be explained in terms of the site transformation, of interstitial Cu atoms in the ZnSe substrate, into Cu atoms which occupied the Zn lattice site. The treatment was suggested to be very useful for improving the purity of homo-epitaxial ZnSe layers.

Suppression of Cu Diffusion from a Bulk ZnSe Substrate to a Homoepitaxial Layer by Se-Beam Irradiation as a Pregrowth Treatment. Y.Hishida, T.Toda, T.Yoshie, K.Yagi, T.Yamaguchi, T.Niina: Applied Physics Letters, 1994, 64[25], 3419-21