Effect of Compensation Degree on the Detecting Properties of In-doped Cd0.9Zn0.1Te crystals

Abstract

The electrical characteristics of In-doped Cd0.9Zn0.1Te (CZT:In) crystals with concentration of  Со = 3,5×1017 cm-3, which are used in X- and gamma-radiation detectors, were investigated. CZT:In crystals possess a weakly pronounced n-type conductivity and had a resistivity of (1 ¸ 2)*109 Ohm´cm at 293 K. In/CZT:In/In structures with ohmic contacts and Cr/CZT:In/In structures with Schottky barriers were created on their base. The temperature dependences of the resistivity in investigated material were analyzed and explained. The energy position of the deep level responsible for the material’ dark conductivity was found. Due to the study of the temperature dependencies of currents limited by space-charge and of currents of the ohmic section of the volt-ampere characteristics (I-VC), the compensation degree of CZT:In crystals is determined. It was found that Cr/CZT:In/In structures with a Schottky diode, fabricated on crystals with a lower compensation degree, possessed the best detection properties than similar structures fabricated on crystals with a greater compensation degree.