Fast High-Flux Response of CdZnTe X-Ray Detectors by Optical Manipulation of Deep Level Defect Occupations

We experimentally investigate the possible correlation between high hole-trap concentrations in wide-bandgap semiconductors and delayed temporal response of high-flux x-ray detector devices to changing photon fluxes. We show that fast photo-current response can be achieved with (1) CdZnTe detectors with high hole mobility-lifetime products, (2) temperature increased detrapping, and (3) constant below-bandgap energy light illumination that modifies the dark defect occupation towards a steady-state with a reduced concentration of active hole traps. This way, the detector signal stabilizes immediately upon flux onset, independent of details of the semiconductor´s point defect structure. Quasi-instantaneous response stabilization (<; 3 ms) to x-ray flux changes > 10⁷ photons mm^-2 s^-1 is demonstrated.