High-performance visible-blind GaN-based p-i-n photodetectors

We report high performance visible-blind GaN-based p-i-n photodetectors grown by metal-organic chemical vapor deposition on c-plane sapphire substrates. The dark current of the 200 mu m diameter devices was measured to be lower than 20 pA for bias voltages up to 5 V. The breakdown voltages were higher than 120 V. The responsivity of the photodetectors was similar to 0.23 A/W at 356 nm under 5 V bias. The ultraviolet-visible rejection ratio was 6.7x10(3) for wavelengths longer than 400 nm. (C) 2008 American Institute of Physics.