We report on the optical properties of the InGaN-based red LED grown on a c-plane sapphire substrate. Blue emission due to phase separation was successfully reduced in the red LED with an active layer consisting of 4-period InGaN multiple quantum wells embedding an AlGaN interlayer with the Al content of 90% on each quantum well. The light output power and external quantum efficiency at a dc current of 20 mA were 1.1 mW and 2.9% with the wavelength of 629 nm, respectively. This is the first demonstration of a nitride-based red LED with the light output power exceeding 1 mW at 20 mA.

No abstract

No abstract

No abstract

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.