High-performance vacuum-ultraviolet (VUV) photodetectors are of great significance to space science, radiation monitoring, electronic industry and basic science. Due to the absolute advantages in VUV selective response and radiation resistance, ultra-wide bandgap semiconductors such as diamond, BN and AlN attract wide interest from researchers, and thus the researches on VUV photodetectors based on these emerging semiconductor materials have made considerable progress in the past 20 years. This paper takes ultra-wide bandgap semiconductor filterless VUV photodetectors with different working mechanisms as the object and gives a systematic review in the aspects of figures of merit, performance evaluation methods and research progress. These miniaturized and easily-integrated photodetectors with low power consumption are expected to achieve efficient VUV dynamic imaging and single photon detection in the future.

Vacuum-ultraviolet (VUV) photon detection technology is an effective means for the exploration in the field of space science (monitoring the formation and evolution of solar storms), high-energy physics (dark matter detection), large-scale scientific facility (VUV free electron lasers) and electronic industry (high-resolution lithography). The advancement of this technology mainly depends on the performance optimization of VUV photodetectors. In this review, we introduced the research progress on the typical VUV photodetectors based on scintillator, photomultiplier tube, semiconductor, and gas, with their unique advantages and optimal performance indicators in different applications summarized. In particular, during recent years, thanks to the advances in ultra-wide bandgap semiconductors, economical VUV photodetectors with low power consumption and small size have been encouragingly developed. Finally, we pointed out the remaining challenges for each type of VUV detector, with the aim of maximizing the performance in a variety of applications in the future.

Vacuum‐ultraviolet (VUV) photodetection is effective in probing the evolution and eruption of solar storms which are destructive to power transmission and communication systems. To realize real‐time monitoring of solar storms, astro‐ and solar physicists are dedicated to developing zero‐energy‐consumption VUV photovoltaic devices with high sensitivity. However, due to the lack of VUV transparent electrodes and high‐quality VUV photosensitive materials, the desired VUV photovoltaic devices with rapid temporal response are rarely reported. Here, graphene is used as the VUV transparent electrode, and a heterojunction device p‐Gr/AlN/n‐ZnO with p–i–n characteristics is fabricated. Benefitting from the lattice‐matched epitaxial growth of AlN film, the device realizes selective photovoltaic response to VUV light. More importantly, by employing a heat annihilation trap state mechanism, the response speed and responsivity of the device are increased by one order of magnitude. This strategy can also be applied to other multispectral photovoltaic devices, which provides a reference for the future development of new‐generation ultrafast monitoring space sensors.

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Unlike traditional three-dimensional semiconductors, when van der Waals semiconductors are integrated to other materials, "lattice mismatch" in the vertical direction can be avoided because there is no dangling bond on their plane surfaces. Here, taking full advantage of the benefit of van der Waals heterostructure, we constructed the first vacuum-ultraviolet photovoltaic device of graphene/hexagonal boron nitride (h-BN)/silicon carbide (SiC), which shows ultrahigh performance on VUV photodetection and is expected to meet the requirements for space exploration. The device is the van der Waals photovoltaic device with the shortest response cutoff wavelength (which is located at 227 nm) reported so far. At 0 V bias, the device exhibits an ultrafast response time of 680 ns, which is 2−3 orders of magnitude faster than that of photoconductive h-BN photodetectors. Our work breaks new ground for the application of van der Waals materials and devices and opens up a potential application scenario in the future, in which space exploration is dependent on VUV photodetection.