OPEN-TUBE SOLID-STATE DIFFUSION OF ZN INTO N-TYPE GAAS0.35P0.65 FROM ZNO OXIDE-FILMS AND ELECTROLUMINESCENCE

A thermal annealing method was utilized in the diffusion process of Zn in the formation of the p-type layer on GaAs0.35P0.65 films. The ther mal diffusion of Zn from the ZnO source film on the n-type substrate p rovides for the formation of a p-type layer and shows a stable signal of electroluminescence. The Zn diffusion mechanism was investigated by introducing two distinct processes of diffusion and reaction into the kick-out model involving Ga Frenkel defects at the diffusion front. T he interstitial diffusion process requires an activation energy of 5.3 eV which is much larger than the substitutional reaction energy of 3. 5 eV. The Zn diffusion process through the interstitial-substitutional exchange of Zn ions is governed by the diffusion-limited process. Fur thermore, the Ga out-diffusion is related to the Frank-Turnbull model involving Schottky defects at the surface. The dissociation of the com positions of the GaAs0.35P0.65 layer into the GaAs-like phase on the f ilm surface was observed by room-temperature photoluminescence. (C) 19 98 American Institute of Physics. [S0021-8979(98)02203-8].