Enhanced Ga2O3/SiC ultraviolet photodetector with graphene top electrodes

Abstract Heterojunctions of β -Ga 2 O 3 /4H SiC are fabricated to form ultraviolet (UV) photodetectors by grown epitaxial β -Ga 2 O 3 films on n-type 4H SiC substrates using laser molecular beam expitaxy technique. By replacing the top electrodes from Au/Ti to single-layer graphene, the devices show more obvious rectifying characteristics and enhanced UV photoresponse. The I light /I dark under 254 nm illumination increases from 4.81 to 63.31 and the responsivity increases from 7.14 × 10 −4  A/W to 0.18 A/W. Our results suggest that the graphene transparent electrodes can not only allow the majority of the incident light to reach the contact area but also offer an easy carrier transport channel when the electron-holes were separated.