Electron mobility and lifetime mapping of CZT with known crystalline defects by pulsed laser excitation

A pulsed laser method is used to map the charge collection amplitude and electron mobility-lifetime product (¿_e¿_e) in Cd_1-xZn_xTe (x = 0.1) pieces especially selected to include regions with crystallographic defects. Additionally, ultrasound imaging is used in conjunction with X-ray diffraction in order to localize and analyze the defects. The defect regions studied include twins, misoriented secondary grains, and Te inclusions. Specific defect types were observed to degrade the local charge collection efficiency with a characteristic magnitude and spatial distribution. Coherent grain boundaries associated with the twin were less affecting than high angle, incoherent boundary associated with second grains. We consider the feasibility of in-line inspection at an early stage of device manufacture by 2D mapping of electron transport properties over large CZT wafer sizes.