A Photoconductive X-ray Detector with a High Figure of Merit Based on an Open-Framework Chalcogenide Semiconductor

A wide range of tunability in the physical parameters of a semiconductor used for X-ray detection is desirable to achieve targeted performance optimization. However, in a dense-phase semiconductor, fine-tuning one parameter often leads to unwanted changes in other parameters. Herein, the intrinsic openness in an open-framework semiconductor has been confirmed, for the first time, to be a key structural factor that weakens the mutual exclusivity of the adjustable physical parameters owing to a non-linear control mechanism. The controllable doping of S in a zeolitic In-Se host results in an optimal balance between resistivity, band gap, and carrier mobility, which finally results in an excellent X-ray detector with a high figure of merit for the mobility-lifetime product (7.12×10^-4  cm²  V^-1 ); this value is superior to that of a commercial α-Se detector. The current strategy of choosing open-framework semiconductor materials opens a new window for targeting high-performance X-ray detection.