An investigation was made of the diffusion of Zn in n-GaAs/Zn-AlGaAs/Se-AlGaAs structures during the growth of n-GaAs layers which were doped with Se and Si. It was found that the diffusion of Zn in these structures depended strongly upon the type of dopant as well as upon the carrier concentration in the n-GaAs layer. The amount of Zn which diffused into both n-GaAs and Se-AlGaAs layers was much smaller for a Si-doped GaAs layer than for a Se-doped layer. The slower diffusion which occurred during the growth of Si-doped GaAs layers in these structures could be reasonably well explained by modifying a model in which interstitial Ga which diffused from the n-GaAs layer and into the Zn-AlGaAs layer was supposed to kick out substitutional Zn. The density of interstitial Ga in the Si-doped GaAs layer could be lower than in the Se-doped GaAs because the interstitial Ga atoms replaced Si which occupied the column-III site. This was not the case for Se-doped GaAs, where Se occupied the column-V site.

N.Fujii, T.Kimura, M.Tsugami, T.Sonoda, S.Takamiya, S.Mitsui: Journal of Crystal Growth, 1994, 145[1-4], 808-12