Rejection ratio and responsivity of dual-layer III-nitride alloy photodetectors

Abstract The III-Nitride alloys (AlGaN and InGaN) photodetectors with Schottky barriers have been studied, focusing on two structures with active layers: one based on Al 0.25 Ga 0.75 N/GaN semiconductors and the other on an In 0.05 Ga 0.95 N/GaN heterostructure. For an overall efficiency of 70%, both proposed devices exhibit remarkable responsivity. The AlGaN structure achieves a responsivity of 111.25 A W −1 at 2 V, while the InGaN device attains 4.302 A/W under the same voltage. At an applied voltage of 8 V, the responsivity of the AlGaN device increases to 83.73 A W −1 , compared to 34.42 A/W for the InGaN device. When operating at 10 V, the AlGaN structure achieves a responsivity of 105 A W −1 , whereas the InGaN device reaches only 6.84 A W −1 . At room temperature, the visible rejection ratio for the Al 0 . 25 Ga 0.75 N/GaN device is 3.33 × 10 4 at 10 V, a high value that indicates the superior performance of the Al 0 . 25 Ga 0.75 N photodetector. In comparison, the In 0.05 Ga 0.95 N/GaN-based photodetector achieved a value of 2.935 at 10 V. Additionally, the maximum photocurrent obtained was 3.045 mA for the Al 0 . 25 Ga 0.75 N device at 10 V and 0.0472 mA for the In 0.05 Ga 0.95 N device at the same voltage.