Wide‐Bandgap Rare‐Earth Iodate Single Crystals for Superior X‐Ray Detection and Imaging
Xieming Xu, Fang Wang, Weiwei Xu, Hao Lü, Lingfei Lv, Hongyuan Sha, Xiao‐Ming Jiang, Shaofan Wu, Shuai‐Hua Wang
Abstract
Abstract Semiconductor‐based X‐ray detectors with low detectable thresholds become critical in medical radiography applications. However, their performance is generally limited by intrinsic defects or unresolved issues of materials, and developing a novel scintillation semiconductor for low‐dose X‐ray detection is a highly urgent objective. Herein, a high‐quality rare‐earth iodate Tm(IO 3 ) 3 single crystal grown through low‐cost solution processing is reported with a wide bandgap of 4.1 eV and a large atomic number of 53.2. The roles of IO and TmO groups for charge transport in the Tm(IO 3 ) 3 are revealed with the structural difference between the [101] and crystal orientations. Based on anisotropic responses of material properties and detection performances, it is found that the [] orientation, the path with fewer IO groups, achieves a high resistivity of 1.02 × 10 11 Ω cm. Consequently, a single‐crystal detector exhibits a low dark current and small baseline drifting due to the wide bandgap, high resistivity and less ion migration of Tm(IO 3 ) 3 , resulting in a low detection limit of 85.2 nGy air s −1 . An excellent X‐ray imaging performance with a high sensitivity of 4406.6 µC Gy air −1 cm −2 is also shown in the Tm(IO 3 ) 3 device. These findings provide a new material design perspective for high‐performance X‐ray imaging applications.