Plastic Inorganic van der Waals Semiconductors for Flexible X-ray Detectors

Radiation detectors that are low-cost, portable, and operating at ambient temperature are highly desirable, especially if they are combined with flexibility and miniaturization. Plastic inorganic semiconductors, distinguished by their excellent electrical and mechanical properties, are promising candidates for portable and wearable radiation detectors. Herein, we demonstrate the potential of plastic inorganic van der Waals single crystals as flexible solid-state radiation detectors operating at room temperature. This study discovers that van der Waals materials such as gallium telluride (GaTe) show high plasticity as well as remarkable radiation detection characteristics, including high absorption coefficient and large mobility-lifetime (μτ) product (∼2 × 10^-3 cm² V^-1), which make them high-quality materials for constructing flexible X-ray detectors. The GaTe-based X-ray detector with asymmetric metal electrodes achieved an extremely low electric field of 1 × 10^-4 V μm^-1, and the detection sensitivity is as high as 40980 μC Gy_air^-1 cm^-2. The device performance was unaffected by its bending status, showing superior stability during prolonged exposure to continuous γ-ray radiation (total dose: 5000 Gy). Our research should be easily generalizable to other van der Waals semiconductors for fabricating flexible radiation sensors that can be embedded in curved or deformable systems.