A Ga 2 O 3 /AlN heterojunction for self-powered solar-blind photodetection with high photo-to-dark current ratio and fast response speed

Abstract In this work, the Ga 2 O 3 film was deposited on sapphire substrate by magnetron sputtering technique, then the AlN film was spin-coated onto the Ga 2 O 3 film for constructing the lateral Ga 2 O 3 /AlN heterojunction in order to performing solar-blind photodetection. At zero bias, the device could achieve dark current (I dark ), UV light switching ratio, linear dynamic region ( LDR ), photo responsivity ( R ), and specific detectivity ( D* ) of 1.45 × 10 −13 A, 2.14 × 10 4 , 86.74 dB, 95.95 μ A W −1 and 5.98 × 10 10 Jones, respectively. Moreover, the photodetector displayed short rise and decay time of 90 and 116 ms, suggesting fast response speed. The self-powered operation is owing to the formation of built-in electric field and open-circuit voltage (V oc ) of 0.4 V for separating electron-hole pairs, profiting from the successful establishment of the Ga 2 O 3 /AlN heterojunction with staggered type-II band alignment with large enough conduction band offset.