Van der Waals heterostructure of BixIy for ultra-sensitive x-ray detection

Abstract X-ray detectors need to be operated at as low as possible doses to reduce radiation health risks during x-ray security examination or medical inspection, which drives the efforts to explore novel detectors with high sensitivity and low detection limits. Organolead trihalide perovskite is the champion, with the highest sensitivity and lowest detection limit. Unfortunately, these materials threaten the safety of the human body and environment by the toxic issue of lead. Here we present a new environmentally friendly material with van der Waals heterostructure of BixIy for ultra-sensitive x-ray detection. The BixIy detector provides anisotropic x-ray detecting performance with a sensitivity up to 1.3×105 µC Gy− 1 cm− 2 and a detection limit as low as 34 nGy s− 1. Meanwhile, our BixIy detector demonstrates wonderful environmental and hard radiation stabilities. Our discovery inspires the search for new van der Waals heterostructure classes to realize high-performance x-ray detectors and other optoelectronic devices without employing toxic elements.