Influence of annealing temperature on structure and photoelectrical performance of β-Ga2O3/4H-SiC heterojunction photodetectors

Abstract In this manuscript, an ultralow dark current solar-blind photodetector based on β-Ga 2 O 3 /4H-SiC heterojunction is generated by depositing β-Ga 2 O 3 thin film on n-type 4H-SiC substrates using Pulse Laser Deposition method. It is found that the excellent performances of our device with ultralow dark current (0.167 nA) as well as high I photo /I dark ration (384.3) are obtained with thermal annealing at optimized temperature, which is due to the improvement of interface defects in the β-Ga 2 O 3 /4H-SiC heterojunction through high temperature annealing. Moreover, the detectivity and linear dynamic range of the device are high as 8.23 × 10 11 Jones and 51.70 dB, respectively, along with faster response speed (a rise time of 0.18 s and a decay time of 0.31s), which are attributed to the co-effect of reducing in defects at the interface of heterojunction and the existence of appropriate amount of mixed-crystal orientation in β-Ga 2 O 3 films with the optimizing the annealing temperature. The electronic transport mechanism in the β-Ga 2 O 3 /4H-SiC heterojunction photodetector is proposed in details with the energy band diagram.