Gao Yuanhong, Ge Yongshuai, Wang Xinwei, Liu Jin, Liu Wenquan, Cao Yong, Gu Kaichen, Guo Zheng, Wei Yu-Ming, Zhou Ni, Yu De, Meng Hong, Yu Xue-Feng, Zheng Hairong, Huang Wei, Li Jia
Materials Interfaces Center, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China.
Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China.
Adv Mater. 2021 Aug;33(32):e2101717. doi: 10.1002/adma.202101717. Epub 2021 Jul 5.
Most contemporary X-ray detectors adopt device structures with non/low-gain energy conversion, such that a fairly thick X-ray photoconductor or scintillator is required to generate sufficient X-ray-induced charges, and thus numerous merits for thin devices, such as mechanical flexibility and high spatial resolution, have to be compromised. This dilemma is overcome by adopting a new high-gain device concept of a heterojunction X-ray phototransistor. In contrast to conventional detectors, X-ray phototransistors allow both electrical gating and photodoping for effective carrier-density modulation, leading to high photoconductive gain and low noise. As a result, ultrahigh sensitivities of over 10 μC Gy cm with low detection limit are achieved by just using an ≈50 nm thin photoconductor. The employment of ultrathin photoconductors also endows the detectors with superior flexibility and high imaging resolution. This concept offers great promise in realizing well-balanced detection performance, mechanical flexibility, integration, and cost for next-generation X-ray detectors.
大多数当代X射线探测器采用具有非增益/低增益能量转换的器件结构，因此需要相当厚的X射线光电导体或闪烁体来产生足够的X射线感应电荷，这样一来，薄型器件的诸多优点，如机械柔韧性和高空间分辨率，就不得不被牺牲。通过采用异质结X射线光电晶体管这种新的高增益器件概念，这一困境得以克服。与传统探测器不同，X射线光电晶体管允许进行电门控和光掺杂以实现有效的载流子密度调制，从而实现高光电导增益和低噪声。结果，仅使用约50nm厚的光电导体就能实现超过10 μC Gy⁻¹ cm⁻²的超高灵敏度以及低检测限。超薄光电导体的使用还赋予探测器卓越的柔韧性和高成像分辨率。这一概念在实现下一代X射线探测器平衡的检测性能、机械柔韧性、集成度和成本方面具有广阔前景。
