Energy-dependent X-ray detectors can provide substance-specific information, enabling multicolor imaging and accurate material discrimination. It is of significance to explore photoelectron extraction mechanisms that can realize energy-dependent X-ray detection. Here, we report an X-ray detector with energy-dependent characteristics based on the field emission mechanism from a methylammonium lead tribromide (MAPbBr3) single crystal (SC). The relationship between the photoelectron energy and the vacuum barrier was investigated by analyzing the carrier extraction dynamics. An energy-dependent detection mechanism was established by considering the surface barrier-controlled hot electron emission process. Moreover, by introducing surface structure with enhanced field enhancement through direct laser patterning, more obvious energy-dependent X-ray response characteristics were observed, which further verified the hot-electron-assisted photoelectron extraction mechanism. This work demonstrates a distinctive energy-dependent X-ray detection approach, which can make full use of the excellent absorption and carrier transport properties of perovskites and the advantages of both vacuum devices and field electron emission phenomena.
Wen et al. (Sun,) studied this question.