Crystal growth and characterization of detector grade (Cd,Zn) Te crystals

(Cd,Zn)Te crystals were grown from the melt by the Bridgman method with diameters of 25 and 75 mm. The material was doped with indium. The structural quality of the crystals was constantly improved to increase the single crystalline areas. These improvements reduced the number of grains in the 25 mm and 75 mm diameter, respectively. The grown material with 25 m diameter are nearly single crystal. The crystals were characterized by electrical and optical methods for evaluation of the relation of structural quality and material properties. By the optimization of the crystal growth a reduction of the etch pitch density down to 2 times 10³ 1/cm² could be achieved. The resistivity of the crystals was in the range of 2 times 10⁹ up to 5 times 10¹⁰ Omegacm The detector performance was tested with different radiation sources. The product of mobility-lifetime of charge carriers was 3 times 10^-3 cm²/V. The energy resolution for different radiation energies were measured for detector thickness of 1 mm and 10 mm.