GaSe/<i>β</i>-Ga₂O₃ heterojunction based self-powered solar-blind ultraviolet photoelectric detector

Abstract

UV photodetectors have the advantages of high sensitivity and fast response speed. As an ultra-wide bandgap semiconductor, gallium oxide (Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) plays an extremely important role in the field of deep ultraviolet detection. It can form a typical type II heterostructure with GaSe, which promotes carrier separation and transport. In this paper, Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; epitaxial films were grown on sapphire substrates by plasma-assisted chemical vapor deposition (PECVD). GaSe films and GaSe/β-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; heterojunction photodetectors were grown on gallium oxide films by Bridgeman technology. The detector has a good response to deep ultraviolet light, the dark current of the device is only 1.83 pA at 8 V, and the photocurrent reaches 6.5 nA at 254 nm. the UVC/Visible (254 nm/600 nm) has a high rejection ratio of about 354. Although at very small light intensities, the responsivity and detection reach 1.49 mA/W and 6.65× 10&lt;sup&gt;11&lt;/sup&gt; Jones. At the same time, due to the photovoltaic effect formed by the space charge region at the junction interface, the detector exhibits self-power supply performance at zero bias voltage, and the open-circuit voltage is 0.2 V. In addition, the detector has a very good sensitivity, whether it is irradiated with different light intensities under the condition of constant voltage, or changing the voltage under the condition of constant light intensity, the device can respond quickly. It can respond within milliseconds under a bias voltage of 10V. This paper demonstrates the enormous potential of heterojunctions in photoelectric detection by analyzing the photophysical and interface physical issues involved in heterojunction photodectectors, and provides a possibility for the deep ultraviolet detection of gallium oxide.