Solar-blind AlGaN-based p-i-n photodetectors with high breakdown voltage and detectivity

We report on the high performance solar-blind AlGaN-based p-i-n photodetectors that are 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 on the order of 5 fA for bias voltages up to 10 V. The breakdown voltages were higher than 200 V. The responsivities of the photodetectors were 0.052 and 0.093 A/W at 280 nm under 0 and 40 V reverse biases, respectively. We achieved a detectivity of 7.5x10(14) cm Hz(1/2)/W for 200 mu m diameter AlGaN p-i-n detectors. (c) 2008 American Institute of Physics.