Preparation and UV detection performance of Ti-doped Ga2O3/intrinsic-Ga2O3/p-Si PIN photodiodes

In this work, PIN-structured photodiodes were fabricated by sputtering intrinsic-Ga2O3 and n-Ga2O3 with various Ti doping concentrations sequentially on p-Si substrates using dual-target RF magnetron co-sputtering technology. The prepared Ga2O3 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 mu W 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.

Automated summary

PIN-structured photodiodes were fabricated by sputtering intrinsic-Ga2O3 and n-Ga2O3 with Ti doping on p-Si substrates. The fabricated Ga2O3 films were amorphous, and the roughness increased with Ti doping concentration. The photodiodes showed high reverse breakdown voltages, significant photoelectric response to 254 nm UV light, and high responsivity at -10 V bias.