High-power AlGaInN flip-chip light-emitting diodes

Data are presented on high-power AlGaInN flip-chip light-emitting diodes (FCLEDs). The FCLED is flipped-over or inverted compared to conventional AlGaInN light-emitting diodes (LEDs), and light is extracted through the transparent sapphire substrate. This avoids light absorption from the semitransparent metal contact in conventional epitaxial-up designs. The power FCLED has a large emitting area (similar to0.70 mm(2)) and an optimized contacting scheme allowing high current (200-1000 mA, J similar to 30-143 A/cm(2)) operation with low forward voltages (similar to2.8 V at 200 mA), and therefore higher power conversion (wall-plug) efficiencies. The improved extraction efficiency of the FCLED provides 1.6 times more light compared to top-emitting power LEDs and ten times more light than conventional small-area (similar to0.07 mm(2)) LEDs. FCLEDs in the blue wavelength regime (similar to 435 nm peak) exhibit similar to 21% external quantum efficiency and similar to 20% wall-plug efficiency at 200 mA and with record light output powers of 400 mW at 1.0 A. (C) 2001 American Institute of Physics.