III-V nitride-based blue LDs with modulation-doped strained-layer superlattices

InGaN multi-quantum-well-structure (MQW) laser diodes (LDs) with Al_0.14Ga_0.86N/GaN modulation doped strained-layer superlattice (MD-SLS) cladding layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 hours under room-temperature continuous-wave operation. The use of the MD-SLS was effective in reducing the operating voltage of the LDs. The ELOG substrate was used to reduce the number of threading dislocations in the InGaN MQW structure. After 2 μm etching of the ELOG substrate, the etch pit density was about 2×10⁷/cm ² in the region of the 4-μm-wide stripe window, but almost zero in the region of the 8-μm-wide SiO₂ stripe