Low noise AlGaN metal-semiconductor-metal photodiodes

Low noise AlGaN metal-semiconductor-metal photodiodes AlGaN metal-semiconductor-metal photodiodes with a sharp cutoff wavelength as short as 310 nm are reported for the first time. The devices show a low dark current, < 0.3 µA at 40 V. The responsivity is flat over the bandgap, with a high visible rejection. At 28 V bias, the noise equivalent power is lower than 17 pW/Hz1/2 and ~24 pW/Hz1/2 in GaN and Al0.25Ga0.75N photodiodes, respectively.