Improved characteristics of InGaN multiple-quantum-well laser diodes grownon laterally epitaxially overgrown GaN on sapphire

InGaN multiple-quantum-well laser diodes have been fabricated on fully coal esced laterally epitaxially overgrown (LEO) GaN on sapphire. The laterally overgrown "wing" regions as well as the coalescence fronts contained few or no threading dislocations. Laser diodes fabricated on these low-dislocatio n-density regions showed a reduction in threshold current density from 10 t o 4.8 kA/cm(2) compared to those on conventional planar GaN on sapphire. Th e internal quantum efficiency also improved from 3% for laser diodes on con ventional GaN on sapphire to 22% for laser diodes on LEO GaN on sapphire. ( C) 2000 American Institute of Physics. [S0003-6951(00)00505-2].