High-Gain AlGaN Solar-Blind Avalanche Photodiodes

This letter reports high performance AlGaN solar-blind avalanche photodiodes (APDs) with separate absorption and multiplication structure grown by metal-organic chemical vapor deposition on AlN templates. In fabricating APD devices, we applied a photo-electrochemical treatment process after mesa etching to reduce damage induced by etching. After introducing this process, the leakage current of the fabricated devices was reduced obviously and a record-high gain of 1.2 x 10(4) at the reverse bias of 84 V was achieved under the measurement condition with the protection current constrained to 10(-5) A.