Vapor Growth of Al-Doped ZnTe by the Closed-Tube Method

The vapor growth of n-type ZnTe on as-grown ZnTe and GaSb substrates was examined at comparatively low temperature by the conventional closed-tube process using minute amounts of iodine as the transport agent. Polycrystalline ZnTe doped with either 5 or 10 mol% Al was used as the source crystal in the doping experiment. A uniform over-growth of ZnTe on the substrates was observed when iodine at a density of 0.6–13×10 -5 mg/cm 3 was introduced into the reaction tube and vapor growth in the 650–675°C system was carried out rather than in the 600–625°C or 625–650°C systems. SIMS measurement showed that the ZnTe layer was doped with a considerable amount of Al. The hot-probe method showed n-type conduction in the layer.