Vertical α/β-Ga2O3 Phase junction Nanorods Array with Graphene-Silver Nanowire Hybrid Conductive Electrode for High-Performance Self-powered Solar-Blind Photodetectors

Abstract Gallium oxide semiconductor, with a bandgap energy of 4.9 eV, is regarded as hopeful candidate for next generation solar-blind photodetectors. However, the construction of photodetector based on Ga2O3 pn junction is still challengeable due to immature doping technology of p-Ga2O3. Considering small lattice mismatch (＜3 %) and similar band gap structure of α-Ga2O3 and β-Ga2O3, a well-designed solar-blind photodetector based on vertical α/β-Ga2O3 junction nanorod arrays (NRAs) with a graphene-silver nanowires (Ag NWs) hybrid top electrode was built. Thanks to the high conductivity and optical transmittance of graphene-Ag NWs top electrode, the photodetector based on α/β-Ga2O3 junction NARs displayed excellent photoelectric performance. Meanwhile, the matched band structure of Π type formed at the interface of α/β-Ga2O3 junction promoted the automatical separation of photogenerated carriers and their transferring to the corresponding electrodes. A fast photoresponse time of 0.54 s, a high light-to-dark ratio about 2000 and a high rejection ratio (R254/R365) of 2.7×103 under the zero bias were realized. The excellent photoelectrical performance of α/β-Ga2O3 junction photodetector even in vacuum environment forecasts its potential application in some low air density fields such as missile early warning and tracking and ozone hole monitoring.