Doping dependent ZnCdSe/ZnSe-superlattice disordering

The doping dependent intermixing of ZnCdSe/ZnSe superlattices was studied by secondary ion mass spectroscopy. The chlorine or nitrogen doped and undoped structures were grown by molecular beam epitaxy. Heat treatment was performed in the temperature range of 300 to 550 °C under different conditions, namely Zn or N atmosphere, vacuum and protected by a Si3N4 cap. The diffusion of Cd was found to be Fickian for all kinds of doping. While identical Cd diffusion coefficients were observed for the undoped and the chlorine-doped superlattice, a distinct enhancement by three orders of magnitude was found for nitrogen-doped structures. The p-type conductivity, and not the nitrogen itself, was identified to be responsible for the Cd diffusion enhancement by additional implantation studies.