Photoconductive characterization of ZnxCd1−xTe (0≤x≤0.25) single crystal alloys

Abstract

Large grain polycrystalline and single crystals of Znx Cd l _ x Te grown by a modified Bridgman method were studied using the photoluminescence and photoconductivity techniques. The temperature dependence of the band gap, as determined by photoluminescence, follows the Varshni equation for measuring temperature in the range of 15-290 K. One of the fitted parameters, the Debye temperature, monotonically decreases with the increase of the atomic zinc concentration. A close correlation between the photoluminescence and photoconductivity measurements is also found. Samples in which the photoluminescence spectra exhibit emission bands associated to cadmium vacancies and other structural defects, show a photoresponse curve which includes, in addition to the intrinsic band, another broad band at lower energies. Using the ionization energies of the defect related bands in the photoluminescence spectra we have identified the second band in the photoresponse curve due to the photoexcitation of trapped carriers at levels related with the structural defects.

Spectral photoelectronic features of TlInSe2single crystals

“…The dc-PC spectra of the TlInSe 2 single crystals were studied in a wide range of the incident photon energy because of the high photosensitivity of these 4 shows the spectral distributions of dc-PC for TlInSe 2 single crystal at the conditional working temperatures ranging from 77 to 300 K. In this experiment, a voltage of 8.0 V was applied to the sample under study and a light intensity of 1200 lx was used for excitation process. The broad band in the room temperature dc-PC spectrum is probably due to the photo-excitation of carriers from states associated with structural defects in bulk single crystals [15]. However, some defects produce centers in the band that steal photon and give small photocurrent.…”

Accurate measurement of electrical bulk resistivity and surface leakage of CdZnTe radiation detector crystals

“…Some of them are taken from published experimental data 7,8 and some have been arbitrarily adjusted to match established low-and room-temperature band gap data of purely binary CdTe and ZnTe. Note that fully compensated ͑n Х p͒ material would still behave n type in a thermoelectric current experiment since the drift mobility of the electrons is much larger than the mobility of the holes ͑ n Ͼ p ͒.…”