Laser-induced transient currents in CdZnTe quasi-hemispherical radiation detector

Laser-induced transient currents were measured after applying pulsed or direct-current bias to a CdZnTe quasi-hemispherical radiation detector with gold contacts. The temporal evolution of current transients was analyzed to evaluate the dynamics of the space charge formation and its spatial distribution. The observed effects were explained by a model involving hole injection from positively biased contacts. Experimental results were complemented by numerical simulations, which supported the model. This paper discusses how the detected phenomena affect the detector performance and proposes an improved detector design.