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  cm 2  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.