Anisotropic X-ray detection performance of melt-grown CsPbBr3 single crystals

Abstract

All-inorganic perovskite CsPbBr₃ has been regarded as a new semiconductor radiation material with great potential due to its excellent carrier transport performance and thermal stability. However, it remains challenging to optimize the size and quality of CsPbBr₃ single crystals for commercial applications. Here, the [100], [010], and [001] orientations of bulk CsPbBr₃ single crystals were examined, and their anisotropic X-ray detection performance was investigated. The regular positive and negative charge distributions at the outer (010) surface and the connection of [PbBr₆]⁴⁻ octahedrons with the [010] orientation contribute to decreased defect densities and enhanced carrier transportation of the (010) facet. Additionally, the wafer with the [010] orientation exhibited the weakest ion migration among the three orientations due to the largest active energy (143.77 meV) and ion diffusion barrier energy (0.361 eV), which is advantageous for enhancing the X-ray response. Moreover, the (010) CsPbBr₃ single crystal detector, which was fabricated with EGaIn and Au electrons, demonstrated the maximum sensitivity of 34 449 μC Gy_air⁻¹ cm⁻² under a high bias voltage of −400 V and the lowest detection limit of 52.6 nGy_air s⁻¹ compared with the other two devices. This work highlights the anisotropic engineering of large-size single crystals for boosting perovskite radiation performance and provides valuable advice for the oriented growth of large-size crystals and films.