Vacuum-Ultraviolet Photovoltaic Detector with Improved Response Speed and Responsivity via Heating Annihilation Trap State Mechanism

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.