Effects of substrate temperature on morphological, structural and photo-electric properties of Cd1−xZnxTe polycrystalline films

Cd_1−xZn_xTe (CZT) films were deposited on ITO substrates at different substrate temperature by repeatedly RF magnetron sputtering with a Cd_0.9Zn_0.1Te target. The effect of substrate temperature on physical properties of CZT films were systematically investigated. The morphology of CZT films were characterized by atomic force and scanning electron microscopes. The grain size increased and grain boundaries decreased with substrates temperature increasing. XRD studies revealed that as-grown CZT films were polycrystalline with (111) preferential orientation and the crystallization quality was improved with the increase of substrate temperature. Optical analysis of CZT films showed the band gap decreased with the substrate temperature increasing. A1 and A2 detectors were fabricated based on the CZT films deposited at 300 and 400 °C, respectively. The electrical and X-ray response properties at room temperature of two detectors were investigated. The dark resistivity is 1.49 × 10⁸ and 4.26 × 10⁸ Ω cm for A1 and A2 detectors, respectively. The X-ray sensitivity of CZT films deposited at 400 °C was higher than that of CZT films deposited at 300 °C.