Boosted UV Photodetection Performance in Chemically Etched Amorphous Gallium(III) Oxide Thin-Film Transistors
Bottom-gate amorphous gallium oxide (Ga2O3) (a-Ga2O3) thin-film transistors (TFTs) were fabricated to boost their UV photodetection properties. A simple chemical-etching solution was employed that is easy to use, low cost, and compatible with traditional lithographic processes to selectively etch a-Ga2O3 films. The a-Ga2O3 channel etched device, on silicon, effectively suppresses gate leakage current. Further, a patterned a-Ga2O3 TFT on quartz shows excellent n-type TFT performance with a high on/off ratio of approximately 107. It is also applied as a phototransistor, to diminish the persistent photoconductivity (PPC) effect while keeping a high responsivity (R). Under 254 nm UV illumination, the a-Ga2O3 phototransistor demonstrated a high light-to-dark ratio of 5 × 107, a high responsivity of R = 5.67 × 103 A W-1, and a high detectivity of 1.87 × 1015 Jones. The PPC phenomenon in a-Ga2O3 UV phototransistors was effectively suppressed by applying a positive gate pulse, which significantly shortens the decay time to 5 ms and enables possible imaging applications.