A bulk Schottky junction for high-sensitivity portable radiation detectors

Abstract The active layer thickness of X-ray detectors needs to reach hundreds of micrometers to absorb X-ray photons, and therefore, high voltages over tens or hundreds of volts should be applied to extract the X-ray generated carriers1-3. The high voltage causes several issues including current drift, performance degradation, and operation insecurity4,5. Here, we propose a bulk Schottky junction (BSJ) for X-ray detector using interpenetrated microporous-carbon electrodes and metal-halide perovskite networks. In the BSJ, the X-ray-generated holes are extracted by the microporous-carbon electrodes under the built-in electric field, while the electrons in the perovskite result in a high gain effect. The BSJ-based detector achieves a high sensitivity of 1.42×105 μC Gyair-1 cm-2 and a low detection limit of 35 nGyair s-1 at a low voltage of -1 V. We fabricate a dry battery-powered portable X-ray alarm prototype which responds 24 times faster than the commercial Geiger-Müller counter tube. The BSJ-based detector maintains 92% of its initial sensitivity after storage for five months and exposure to 28.8 Gyair, equivalent to 144000 chest X-ray examinations. The BSJ-based detector arrays also show remarkable uniformity and decent spatial resolution up to 5.0 lp/mm, demonstrating its potential application in X-ray imaging.