AlGaN-based 280 nm light-emitting diodes with continuous-wave power exceeding 1 mW at 25 mA

Optimization of the migration-enhanced metalorganic chemical vapor deposition and further optimization of the contact and active layer design for 280 nm light-emitting diodes resulted in large improvement of cw and pulsed output power and in a superior spectrum purity. The ratio of the main peak to the background luminescence determined by the detection system is higher than 2000:1 at 20 mA dc. The on-wafer cw power was measured to be 255 muW at 20 mA dc. The power popped up exceeding 1 mW for a packaged device under 25 mA dc and 9 mW under pulse 200 mA. The maximum wall-plug-efficiency of 0.67% was obtained for the packaged device at 25 mA dc. (C) 2004 American Institute of Physics.