A thermal annealing method was used to diffuse Zn during the formation of p-type layers on GaAs0.35P0.65 films. The thermal diffusion of Zn, from a ZnO source film on the n-type substrate, permitted the formation of a p-type layer and produced a stable electroluminescence signal. The Zn diffusion mechanism was investigated by introducing 2 distinct processes, of diffusion and reaction, into a kick-out model which involved Ga Frenkel defects at the diffusion front. The interstitial diffusion process required an activation energy of 5.3eV; which was much larger than the substitutional reaction energy (3.5eV). The diffusion of Zn, via the interstitial-substitutional exchange of Zn ions, was governed by the diffusion-limited process. The out-diffusion of Ga was related to the Frank-Turnbull model which involved Schottky defects at the surface.

C.B.Park, K.Kim: Journal of Applied Physics, 1998, 83[3], 1327-32