Al x Ga 1 − x N -based avalanche photodiodes with high reproducible avalanche gain

The authors report high performance solar-blind photodetectors with reproducible avalanche gain as high as 1560 under ultraviolet illumination. The solar-blind photodetectors have a sharp cutoff around 276nm. The dark currents of the 40μm diameter devices are measured to be lower than 8fA for bias voltages up to 20V. The responsivity of the photodetectors is 0.13A∕W at 272nm under 20V reverse bias. The thermally limited detectivity is calculated as D*=1.4×1014cmHz1∕2W−1 for a 40μm diameter device.