Boron oxide encapsulated Bridgman growth of high purity high resistivity CdTe crystals

High-purity semi-insulating CdTe crystals have been successfully grown by encapsulated (B2O3) Bridgman technique. The procedure strongly limits component losses allowing the achievement of stoichiometry control material and keeps a low level of impurity contamination as shown by mass spectroscopy analysis data. When strictly stoichiometry-controlled and high-purity polycrystalline source material has been used, high-resistivity crystals have been obtained without any intentional doping. EPD values in the range of 1-3×104 cm-2 have been observed in a wide region of the crystals. Luminescence spectroscopy confirms the purity and good structural quality of the material. The proposed method avoids the technical problems posed by the High Pressure Bridgman technique and fits the requirements for CdTe/CdZnTe crystals large-scale production.