InGaN/GaN MQWs green-light photodetectors with thin GaN barrier layers

Green light InGaN photodiodes based on 21-periods In0.31Ga0.69N/GaN MQWs with 6-nm-thick barriers were fabricated and characterized. The fabricated devices show a spectral response cutoff of more than three orders of magnitude by 540 nm. Dark current as low as 2.65×10-14 A was measured at 5 V reverse bias. Responsivity of 69.0 mA/W was obtained at ~490 nm and -5 V bias under the back illumination condition, corresponding to an external quantum efficiency of 12.8 %.