AlxGa1–xN‐based avalanche photodiodes with high reproducible avalanche gain

We report high performance solar‐blind photodetectors with reproducible avalanche gain as high as 1570 under ultraviolet illumination. The solar‐blind photodetectors have a sharp cut‐off around 276 nm. The dark currents of the 40 μm diameter devices are measured to be lower than 8 femto‐amperes for bias voltages up to 20 V. The responsivity of the photodetectors is 0.13 A/W at 272 nm under 20 V reverse bias. The thermally limited detectivity is calculated as D* = 1.4 × 1014 cm Hz1/2 W–1 for a 40 µm diameter device. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)