Self-Powered X-Ray Photodetector Based on Ultrathin PbI 2 Single Crystal

Lead iodide (PbI 2 ) single crystals have been extensively investigated due to their potential applications in nuclear radiation detectors at room temperature. In this letter, the properties of ultrathin PbI 2 single crystals were obtained and investigated by X-ray diffraction, ultraviolet-visible diffuse reflection spectroscopy, and field emission scanning electron microscopy. The X-ray photodetector based on ultrathin PbI 2 single crystal with a Schottky configuration of Au/PbI 2 /Mo was also fabricated through a facile method. Especially, the X-ray photodetector exhibits good stability and reproducibility. A large sensitivity of ${0}.{12} \times {10}^{{4}} \mu \text{C}$ /Gy air /cm 2 was obtained for X-ray photodetector based on PbI 2 single crystal at zero bias under a low radiation dose rate (0.19 mGy/h), which is sixty times higher than that of currently $\alpha $ -Se X-ray detectors at high bias. Moreover, we have further illustrated the working principles of the photodetector at zero, positive and negative bias with and without X-ray illumination. Our investigation substantiates the potential of the self-powered X-ray photodetector based on ultrathin PbI 2 single crystal as a candidate device in optoelectronic applications.