Ba Yanshuang, Zhu Weidong, Xu Zhuangjie, Jiang Shaohua, Yang Mei, Bai Fuhui, Xi He, Chen Dazheng, Zhang Jincheng, Zhang Chunfu, Hao Yue
State Key Laboratory of Wide-Bandgap Semiconductor Devices and Integrated Technology, School of Microelectronics, Xidian University, Xi'an 710071, China.
Guangzhou Wide Bandgap Semiconductor Innovation Center, Guangzhou institute of technology, Xidian University, Guangzhou 510555, China.
ACS Appl Mater Interfaces. 2024 Oct 3. doi: 10.1021/acsami.4c12010.
Polycrystalline lead halide perovskite finds promising use in fabricating X-ray detectors with a large lateral size, adjustable thickness, and diverse synthesis processes. However, a large dark current hinders its development for weak signal detection. Herein, we propose a multistep pressing strategy for manufacturing a CsPbBr/CsPbCl heterojunction wafer for a reduced dark current X-ray detector, and the device keeps a high sensitivity value after the insertion of a barrier by heterojunction; thus, the trade-off between sensitivity and dark current can be broken. The X-ray detector with a metal-semiconductor-metal structure yields a sensitivity of 6.32 × 10 μC Gy cm at a bias of 12 V, a 1/ noise of 1.02 × 10 A/Hz, and a detection limit of 66.58 nGy s. These performance parameters are considerably better than those of a similar X-ray detector based on the single-structure wafer. The improved device performance of the heterostructure X-ray detector is ascribed to the suppressed carrier recombination, enhanced carrier transportation of the heterojunction, and strong X-ray attenuation of the CsPbCl layer. The pixel array device is further used in imaging applications. Hence, this study provides an efficient strategy for fabricating heterostructure polycrystalline lead halide perovskite wafers for use in high-performance wafer-based X-ray detectors.
多晶卤化铅钙钛矿在制造具有大横向尺寸、可调节厚度和多种合成工艺的X射线探测器方面具有广阔的应用前景。然而，大的暗电流阻碍了其在微弱信号检测方面的发展。在此，我们提出了一种多步压制策略，用于制造用于降低暗电流X射线探测器的CsPbBr/CsPbCl异质结晶片，并且该器件在通过异质结插入势垒后保持高灵敏度值；因此，可以打破灵敏度和暗电流之间的权衡。具有金属-半导体-金属结构的X射线探测器在12 V偏压下的灵敏度为6.32×10 μC Gy cm，噪声比为1.02×10 A/Hz，检测限为66.58 nGy s。这些性能参数明显优于基于单结构晶片的类似X射线探测器。异质结构X射线探测器器件性能的提高归因于载流子复合的抑制、异质结载流子传输的增强以及CsPbCl层对X射线的强衰减。像素阵列器件进一步用于成像应用。因此，本研究为制造用于高性能基于晶片的X射线探测器的异质结构多晶卤化铅钙钛矿晶片提供了一种有效的策略。
