Transport and noise properties of CdTe(Cl) crystals

Experimental studies of transport and noise characteristics of CdTe (Cl dop ed) crystals, prepared by travelling heater method, have been carried out. The basic material is of p-type with p = 1.8 x 10(14) m(-3), mu (h) = 0.006 5 m(2) V-1 s(-1), mu (o) = 0.13 m(2) V-1 s(-1). The current and noise spect ral density was measured as a function of the sample illumination, voltages across the sample and incident light wavelengths. Two types of effective c harge carrier mobility are assumed: namely, the effective transport mobilit y, which is 0.065 m(2) V-1 s(-1) and the effective noise mobility, which re aches a value of 0.125 m(2) V-1 s(-1), both for high illumination. Under th e same conditions, the density of light generated charge carrier pairs is 1 .7 x 10(15) m(-3). Experimental results are in a good agreement with the fo ur-level recombination model. The values of 1/f noise parameter alpha range from 4 x 10(-4) to 2.5 x 10(-3). The alpha parameter grows with almost the photocurrent square root. The signal-to-noise ratio improves if the electr ic field strength in the CdTe detector is set to a higher value. (C) 2001 E lsevier Science Ltd. All rights reserved.