Ultrathin and Ultrasensitive Direct X-ray Detector Based on Heterojunction Phototransistors

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(5) mu C Gy(air)(-1) cm(-2) with low detection limit are achieved by just using an approximate to 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.

Automated summary

By adopting a new high-gain device concept of heterojunction X-ray phototransistor, ultrahigh sensitivities and low noise can be achieved in thin devices, while maintaining mechanical flexibility and high spatial resolution. This offers great promise for next-generation X-ray detectors in terms of balanced detection performance, flexibility, integration, and cost.