Improved β-Ga2O3 Solar-Blind Deep-Ultraviolet Thin-Film Transistor Based on Si-Doping

Gallium oxide (Ga2O3)-based photodetectors are attracting more and more attention for their wide range of applications in optical imaging, spatial communication, etc. In this work, solar-blind deep-ultraviolet thin-film transistors (TFTs) based on polycrystalline β-Ga2O3 thin film were constructed by pulsed laser deposition. The photoelectric performance of β-Ga2O3 TFT is effectively improved by a Si-doping method. The turn-on voltage (Von) of Si-doped β-Ga2O3 TFT is negatively shifted by 20 V, exhibiting enhancement-mode (E-mode) operation. The optimized Si-doped Ga2O3 TFT photodetector shows a high on/off ratio of ~ 105, a turn-off current (Ioff) of ~ 10−11 A at drain voltage (VD) = + 20 V, responsivity (R) of 3.23 A/W, detectivity (D*) of 4.41 × 1013 Jones, and a photocurrent/dark current (Ilight/Idark) of ~ 104 at gate voltage (VG) = − 5 V, VD = + 20 V under 254 nm light. The obtained results suggest that the Si-doping method can effectively modulate the Von of β-Ga2O3 TFT and promote photoelectric performance.