247 nm solar-blind ultraviolet p-i-n photodetector

Abstract

We describe solar-blind p-i-n photodetectors based on short period superlattices of AlN/Al0.08Ga0.92N. The devices are grown using gas source molecular beam epitaxy with ammonia on transparent sapphire substrates. The cutoff wavelength for the device is 247 nm. For diodes with 150 m diameter mesas and sidewall surfaces passivated in oxygen plasma, we obtain extremely low dark leakage current of 3 pA/cm2 and high zero-bias resistance of 6 1014 . At 10 V reverse bias the observed responsivity is 62 mA/W.