Large-area CdZnTe thick film based array X-ray detector

Abstract

Large-area and high-crystallinity CdZnTe (CZT) thick films are grown by physical vapor transport and vacuum thermal evaporation (PVT-VTE) hybrid method. The structure, morphology and composition of which are characterized by X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The as-grown CZT thick films are polycrystalline with (111) preferential orientation, which has a dense pyramid surface structure and a thickness of 590 μm. An 8 × 8 array pixilated X-ray detector is fabricated based on the CZT thick film. The average dark resistivity of 8 pixels on the detector diagonal is up to 3.33 × 1011 Ω cm. The estimated mobility-lifetime product of the CZT array detector is 0.72 × 10−2 cm2V−1. Film structure makes the corresponding detector reduce the influence of trapping effect on the charge carrier transport along the grain growth direction, which shows a short relaxation time and fast photocurrent response. The results demonstrate that the CZT thick film based array detector has high resistivity and sensitivity, and the potential to develop X-ray detection and imaging device under room temperature environment.