High-brightness InGaAlP green light-emitting diodes

Abstract

Candela class InGaAlP surface-emission green light-emitting diodes (LEDs) have been successfully fabricated. The growth of InGaAlP on an intentionally misoriented substrate improved emission properties, as confirmed by a quantitative estimation of the diffusion length in the active material. A Bragg reflector using InGaAlP was realized for the first time. A new device structure, including this Bragg reflector, drastically improved the light extraction efficiency. An external quantum efficiency of 0.7% at 573 nm green light was obtained, corresponding to a luminous intensity of 2 cd.