Preparation and UV detection performance of Ti-doped Ga 2 O 3 /intrinsic-Ga 2 O 3 /p-Si PIN photodiodes

In this work, PIN-structured photodiodes were fabricated by sputtering intrinsic-Ga 2 O 3 and n-Ga 2 O 3 with various Ti doping concentrations sequentially on p-Si substrates using dual-target RF magnetron co-sputtering technology. The prepared Ga 2 O 3 films were all amorphous, and the surface RMS roughness increased with the increase of Ti doping concentration. The PIN diodes with Ti concentrations of 4.35 and 6.15 at.% exhibited high reverse breakdown voltages (180 and 160 V, respectively) and significant photoelectric response to 254 nm UV light (70 μW cm −2 ) in the reverse bias state, and the photo-dark current ratio ( I photo / I dark ) at − 100 V bias was 520.9 and 290.3, respectively. The 4.35 at.% Ti-doped photodiode had the highest responsivity up to 0.65 A mW −1 at − 10 V bias, and the rise ( t r ) and decay ( t d ) times were as short as 0.31 s and 0.19 s, respectively. This study provides an easy method for the preparation of high-performance deep UV photodetectors and facilitates their post-integration and low-cost mass production.