GaN ultraviolet avalanche photodiodes fabricated on free‐standing bulk GaN substrates

We report high‐performance MOCVD‐grown GaN ultraviolet (UV) p‐i‐n avalanche photodiodes (APD) on bulk GaN substrates. The fabricated APD achieved avalanche gain of > 3 × 104 and low leakage current density (<10–7 A/cm2) at voltages below 50% of the device avalanche breakdown voltage. To the best of our knowledge, this is the highest linear gain reported to date among III‐N‐based UV APDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)