High-sensitive and fast MXene/silicon photodetector for single-pixel X-ray imaging

The demand for high-performance X-ray detectors leads to material innovation for efficient photoelectric conversion and carrier transfer. However, current X-ray detectors are often susceptible to chemical and irradiation instability, complex fabrication processes, hazardous components, and difficult compatibility. Here, we investigate a two-dimensional (2D) material with a relatively low atomic number, Ti₃C₂T_x MXenes, and single crystal silicon for X-ray detection and single-pixel imaging (SPI). We fabricate a Ti₃C₂T_x MXene/Si X-ray detector demonstrating remarkable optoelectronic performance. This detector exhibits a sensitivity of 1.2 × 10⁷ μC Gy_air⁻¹ cm⁻², a fast response speed with a rise time of 31 μs, and an incredibly low detection limit of 2.85 nGy_air s⁻¹. These superior performances are attributed to the unique charge coupling behavior under X-ray irradiation via intrinsic polaron formation. The device remains stable even after 50 continuous hours of high-dose X-ray irradiation. Our device fabrication process is compatible with silicon-based semiconductor technology. Our work suggests new directions for eco-friendly X-ray detectors and low-radiation imaging system.