Temporal pulsed x-ray response of CdZnTe: In detector

Abstract

The temporal response of cadmium-zinc-telluride (CZT) crystals is evaluated at room temperature by using an ultrafast-pulsed x-ray source. The dynamics of carrier relaxation in a CZT single crystal is modeled at a microscopic level based on a multi-trapping effect. The effects of the irradiation flux and bias voltage on the amplitude and full width at half maximum (FWHM) of the transient currents are investigated. It is demonstrated that the temporal response process is affected by defect level occupation fraction. A fast photon current can be achieved under intense pulsed x-ray irradiation to be up to 2.78×10 9 photons mm −2 •s −1 . Meanwhile, it is found that high bias voltage could enhance carrier detrapping by suppressing the capture of structure defects and thus improve the temporal response of CZT detectors.

Effect of transient space–charge perturbation on carrier transport in high-resistance CdZnTe semiconductor*

“…Time-of-flight technique (TOF) has been widely used to obtain the information about carrier transport properties and distribution of electric field inside a crystal. [14][15][16] Alpha source, x-ray machine, and γ -ray source, which are commonly used in the TOF measurements, usually have the disadvantage of random uncertainty. Therefore, in this study, a pulsed laser is used as an excitation source; this laser has good monochromaticity and can be easily controlled to systematically study the effect of space-charge perturbation on carrier transport process in CdZnTe semiconductor.…”