Abstract: An improved x-ray detector in the form of a p-i-n CdTe homojunction device is disclosed. The intrinsic ("i") layer is of high resistivity CdTe, while the n- and p-doped CdTe layers are epitaxially grown in a photo-assisted process in a molecular beam epitaxial apparatus. The n-dopant is conveniently indium, with an indium metal contact. The "i" layer is optionally epitaxially grown in a photo-assisted process. The p-dopant is preferably arsenic. A PAMBE formed mercury telluride contact layer enhances the ohmic contact to the p-layer, and a gold contact is provided to the contact layer. The use of the PAMBE technique facilitates high quality crystal growth and activation of the dopants. The resulting CdTe p-i-n homojunction device has a wide band gap (1.45 eV) essential to room temperature operation.

Abstract: The invention relates to molecular beam epitaxial (MBE) processing and more particularly to a two zone electrical furnace for use with high vapor pressure II-VI materials. The furnace is designed for use with effusion type crucibles requiring a lower temperature in the fill zone to control the flux and a higher temperature in the orifice zone to avoid clogging the customary collimating orifice. Each zone is heated by a distributively heated radiator, the fill zone radiator being of a tantalum foil construction of low thermal conductance, while the orifice zone radiator is a solid molybdenum cylinder of relatively high thermal conductance. The zones are joined by linking the two radiators by a thermally conductive path, while the shields and the distributed heaters of the respective zones are separated to reduce thermal coupling. The arrangement provides substantial independence between the temperature settings of the two zones and the molybdenum construction is free of erosion from tellurium based reagents.