Dark Conductivity in Semi-Insulating Crystals of CdTe:Sn

We prepared semi-insulating CdTe for radiation detectors by isothermal annealing of single crystals grown by Bridgeman technique in a sealed quartz container filled with Sn vapor. The resistivity of CdTe:Sn samples thus obtained was of order of 10 10 Ohm·cm at room temperature with electrons lifetime of 2´10 -8 s, which is appropriate for the applications desired. Analysis of electric transport characteristics depending on temperature, sample thickness and voltage applied revealed the presence of traps with concentration of about (4-5)´10 12 cm -3 with the corresponding energy level at 0.8 ? 0.9 eV counted from the bottom of conduction band. The conductivity was determined by electron injection from electrodes in space charge limited current mode.