Electron transport and charge induction in cadmium zinc telluride detectors with space charge build up under intense x-ray irradiation

Under intense x-ray irradiation, wide band gap semiconductor radiation detectors fabricated from crystals with low hole transport properties develop a steady-state space charge distribution that results from a dynamic equilibrium between charge carrier dynamics and the incident photon field. At a high enough x-ray flux, this space charge can collapse the electric field within the detector, resulting in the paralyzation of photon counting (i.e., high-flux polarization). However, well before polarization causes a catastrophic device failure, there can be enough space charge present to significantly modify the electric field. A modified field affects the electron transport and, therefore, signal generation within the sensor, which can ultimately degrade the performance of high-rate photon counting electronics. In this study, we analytically solve the fundamental equation of charge conservation to derive the modified electron transport in the presence of an exponential space charge distribution that results f...