Characterization of CdMnTe radiation detectors using current and charge transients

Charge transport characteristics of Cd_0.95Mn_0.05Te: In radiation detectors have been evaluated by combining time resolved current transient measurements with time of flight charge transient measurements. The shapes of the measured current pulses have been interpreted with respect to a concentration of net positive space-charge, which has resulted in an electric field gradient across the detector bulk. From the recorded current pulses the charge collection efficiency of the detector was found to approach 100%. From the evolution of the charge collection efficiency with applied bias, the electron mobility-lifetime product of μ_nτ_n = (8.5 ± 0.4) × 10^-4 cm²/V has been estimated. The electron transit time was determined using both transient current technique and time of flight measurements in the bias range of 100-1900 V From the dependence of drift velocity on applied electric field the electron mobility was found to be μ_n = (718 ± 55) cm²/(V.s) at room temperature.