Polar selenide single crystal LiGa_0.5In_0.5Se₂ with a bulk photovoltaic effect for highly sensitive self-driven X-ray detection

Self-driven X-ray detectors, featuring low energy consumption, compactness, and integrability, are essential in diverse applications including medical imaging, security, and industrial inspection. Unlike the conventional photovoltaic based on Schottky and p-n junctions, the bulk photovoltaic effect (BPVE) enables photoexcited carrier separation in homogeneous polar single crystals, providing a promising mechanism for self-driven X-ray detection. In this study, we present a polar selenide single crystal LiGa_0.5In_0.5Se₂ (LGISe) as a BPVE-driven material for self-driven X-ray detection. Large-sized, high-quality LGISe crystals were successfully grown using the Bridgman growth technique. Photoelectric experiments reveal that the polarization-induced BPVE along the polar <i>c</i>-axis in LGISe facilitates the separation of photoexcited carriers without an external electric field. Leveraging this mechanism, we fabricated LGISe-based self-driven X-ray detectors, achieving a high sensitivity of 354 μC Gy^-1 cm^-2 and a low detection limit of 125.5 nGy s^-1 at zero bias, displaying a clear imaging at a dose rate of 2.944 μGy s^-1. This study highlights the significant potential of LGISe crystals for self-driven X-ray detection and establishes a novel platform for polar selenide materials in next-generation radiation detection technologies.