HIGH-POWER, LONG-LIFETIME INGAN GAN/ALGAN-BASED LASER-DIODES GROWN ONPURE GAN SUBSTRATES/

Epitaxially laterally overgrown GaN on sapphire was used to reduce the number of threading dislocations originating from the interface of th e GaN epilayer with the sapphire substrate. The GaN layer above the Si O2 mask area surrounding the window, corresponding to the lateral over growth, was nearly free of the threading dislocations. A high density of threading dislocations was observed in the vicinity of GaN grown in the window regions. InGaN multi-quantum-well-structure laser diodes ( LDs) grown on pure GaN substrates, which were fabricated by removing t he sapphire substrate, were demonstrated. The LDs with an output power of 5 mW exhibited a lifetime of more than 290 h and an estimated life time of 10,000 h despite a relatively large threshold current density. The far-field pattern of the LDs with a cleaved mirror facet revealed single-mode emission without any interference effects.