Over the past 20 years, astro and solar physicists have been working hard to develop a new-generation semiconductor-based vacuum-ultraviolet (VUV, 100-200 nm) photodetector with small size and low power consumption, to replace the traditional microchannel detection system, which is ponderous and has high energy consumption, and finally to reduce the power load and launch costs of explorer satellites. However, this expectation has hardly been achieved due to the relatively low photoresponsivity and external quantum efficiency (EQE) of the reported VUV photoconductive detectors based on traditional wide-band-gap materials and structures. Here, on the basis of few-layer h-BN, we fabricated a high-performance two-dimensional photodetector with selective response to VUV light. Typically, it has high sensitivity (EQE = 2133%, at 20 V) to the extremely weak 160 nm light (3.25 pW). This excellent photoresponsivity can be attributed to the high carrier collection efficiency and existing surface trap states of few-layer h-BN. In addition, this device can maintain a stable performance in a wide temperature range (80-580 K), which is quite favorable for application in deep space with huge temperature fluctuation.
Keywords: carrier collection efficiency; h-BN; photodetector; trap states; vacuum ultraviolet.