Ultralow Detection Limit and Anisotropic X-Ray Detection Behaviors Based on A Novel Oxide KCsMoP2O9 Single Crystal

X-ray detection has drawn great attention in industrial examination, medical imaging, scientific research, and beyond. Herein, the anisotropic X-ray detection performances are investigated based on a novel oxide crystal KCsMoP2O9 (KCMP). The large dielectric screening effect and 1D infinite chain structure consisting of MoO6 octahedron and two PO4 tetrahedrons are conducive to efficient carrier transport along the X-direction, leading to a higher mu tau (4.77 x 10(-3) cm(2) V-1) of X direction than that of Z direction (1.05 x 10(-4) cm(2) V-1). Additionally, the KCMP-based X-ray detector along the X direction shows weaker ion migration than that of the Z direction due to the large migration barrier of O2- (8.0 eV) and high ion active energy (784.9 meV) along the X direction. Owing to the high resistivity (2.29 x 10(13) Omega cm), high mu tau, high ion activation energy, suppressed ion migration, and ultralow dark current, the X-ray detection performance of the KCMP detector along the X direction is superior to that of the Z direction. Specifically, the high sensitivity (131.2 mu C Gy(-1) cm(-2)) and ultralow detection limit (8.9 nGys(-1)) are achieved in the KCMP detector along the X direction. This work clarifies anisotropic engineering to enhance the X-ray detection performance of oxide crystals and proposes a novel X-ray detection crystal with an ultralow detection limit.