Evaluation of electric field profile and transport parameters in solid-state CZT detectors

Electric field profile and transport parameters from independent measurements on planar CdZnTe spectroscopic detectors were compared. The mobility and lifetime for electrons, together with the electric field profile, were deduced from current transient profiles induced by laser pulses at different applied voltages. The method is founded on a procedure of minimization built up from the Ramo-Shockley theorem and some physical constraints. The procedure was tested on a planar detector built with spectroscopic CdZnTe grown at IMEM-CNR in Parma, Italy. The mobility-lifetime product was also evaluated by fitting the charge collection efficiency curves under a suitable electric field profile model. Comparison between results from both the techniques are in good agreement and confirm the high spectroscopic features of the investigated material.