Leveraging defect-induced internal gain for high-performance β-Ga 2 O 3 photodetectors on patterned sapphire substrates

We presented a deep-ultraviolet (DUV) metal−semiconductor−metal (MSM) photodetector featuring a β-Ga2O3 thin film deposited by chemical vapor deposition (CVD) on a patterned sapphire substrate (PSS), with a side-by-side comparison to a control photodetector fabricated using a β-Ga2O3 film grown on a flat sapphire substrate. To the best of our knowledge, this marks the first successful growth of β-Ga2O3 films exhibiting a preferred (510) crystal orientation. The β-Ga2O3 film grown on PSS showed a high concentration of defects, including structural disorders, oxygen vacancies, and dangling bonds, which contributed to exceptional responsivity (106.5 A/W) and specific detectivity (1.36 × 1013 Jones) due to high internal gain and extrinsic transitions, even with a relatively large dark current. A UV/visible light rejection ratio (R255 / R400) exceeding 104 further validated the device's sensitivity. A comprehensive analysis was conducted on the effect of defects on the elevated dark current and slower response time of the device. These results provide critical insights into the growth mechanism of β-Ga2O3 on PSS, opening new avenues for the development of high-performance, solar-blind photodetectors that are cost-effective, scalable, and optimized for mass production.