Dilute nitride resonant cavity enhanced photodetector with internal gain for the λ ∼ 1.3μm optical communications window

We report on a novel dilute nitride-based resonant cavity enhanced photodetector (RCEPD) operating at 1.286μm. The RCEPD was fabricated using 21 pairs top and 24 pairs bottom GaAs/AlGaAs distributed Bragg reflectors for mirrors and 7nm thick nine GaAs/Ga0.65In0.35N0.02 As0.98 quantum wells as the absorption region. For a 15m diameter window, the photocurrent at 1286nm is 27 μA and 42 μA, at V=0 and 1V respectively, whereas the dark current is as low as 1.7nA at 1V. At the operating wavelength, an excellent wavelength selectivity with a full width at half maximum (FWHM) of 5 nm, and a high quantum efficiency of 43% are demonstrated. The device exhibits significant internal gain at very small reverse bias voltages of V ⩾2V with an overall quantum efficiency of 67%. These are the best ever recorded values for a dilute nitride RCEPD.