InGaN Light-Emitting Diodes on c-Face Sapphire Substrates in Green Gap Spectral Range

High-efficiency InGaN light-emitting diodes (LEDs) in the "green gap" range were fabricated on c-face sapphire (0001) substrates. Optical properties were enhanced by band engineering of active layers and optimization of growth conditions. Output power and external quantum efficiency of 11.0 mW and 24.7% for a 559 nm green-yellow LED and 4.7 mW and 13.3% for a 576 nm yellow LED with the injection current of 20 mA were achieved, respectively.