Transparent ITO gate p-GaN/AlGaN/GaN UV photodetector with high responsivity and high PDCR

In this work, we demonstrate a high-performance UV phototransistor based on p-GaN/AlGaN/GaN HEMTs with a transparent ITO gate. Under subthreshold gate bias and 365 nm UV light source, the peak photo responsivity (R) of the device exceeds $1.2\times$ $10^{7}$A/W, and the photo-to-dark-current ratio (PDCR) of the device also exceeds $\sim 10^{7}$, which is a significant performance improvement compared to traditional phototransistors with thin layers Ni/Au. The responsivity of the prepared device decreased by $\sim 6$ orders of magnitude under light sources above 400 nm, indicating that the device has excellent visible light blindness. This work demonstrates the great potential of p-GaN HEMTs with ITO gates in the field of visible blindness detection.