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 crystals were characterized by electrical and optical methods to evaluate the relation between structural quality and detector performance. A reduction of the etch pitch density down to 2times10³ cm^-2 was achieved by the optimization of the crystal growth The resistivity of the crystals was in the range of 2times10⁹ up to 5times10¹⁰ Omega cm. The detector performance was tested with different radiation sources. The product of mobility-lifetime of charge carriers was 3times10^-3 cm²/V. The energy resolution for different radiation energies were measured for detector thickness of 1 mm and 10 mm.