New HgCdTe VPE structures on Sapphire by using hybrid substrates

Mercury Cadmium Telluride (Hg_1-xCd_xTe) layers have been grown directly on (0001) Sapphire wafers by an isothermal VPE process, starting from MOCVD CdTe/Sapphire hybrid substrates. The complete transformation of the starting CdTe films into HgCdTe alloys is controlled by two physical processes: -the HgTe Vapour Phase Epitaxy and -the HgTe/CdTe solid state interdiffusion. Working under interdiffusion rate conditions higher than the HgTe growth rate, compositionally uniform Hg_1-xCd_xTe layers can be obtained directly on Sapphire substrates. The final Hg_1-xCd_xTe films composition results completely controlled by: -the thickness of the starting MOCVD CdTe layer (grown on Sapphire), and -the HgTe thickness grown during the iso-VPE process. Morphological, optical, structural and electrical characteristics of "as-grown" and "Mercury vacancy annealed" layers will be reported, witnessing the powerful of these new HgCdTe structures.