High-sensitivity nitride-based ultraviolet photosensors with a low-temperature AlGaN interlayer

Nitride-based ultraviolet (UV) photosensors with a low-temperature (LT) AlGaN interlayer were fabricated and characterized. Material analysis results showed that dark pits corresponding to threading dislocation (TD) terminations were almost invisible after inserting the LT AlGaN interlayer. It was also found that we could significantly suppress the dark leakage current by using the LT AlGaN interlayer owing to TD annihilation and demultiplication processes. For photosensors with the LT AlGaN interlayer, the responsivity at 360 nm and UV-to-visible rejection ratio were found to be 0.12 A/W and 2.45 × 10 ³, respectively, under 5 V applied bias.