Enhanced luminescence efficiency due to carrier localization in InGaN/GaN heterostructures grown on nanoporous GaN templates

Low defect density GaN was achieved through dislocation annihilation by regrowing GaN on strain relaxed nanoporous GaN template formed by UV-enhanced electrochemical etching. The InGaN/GaN single and multiple quantum wells grown on this nanoporous GaN template show enhanced indium incorporation due to strain relaxation. The step edges of regrown GaN on these nanoporous GaN act as effective nucleation sites for impinging indium atoms during growth. Evidence shows fluctuation in the quantum well width caused by indium segregation leading to carrier localization. A higher luminescence efficiency of InGaN/GaN quantum wells is achieved through a combination of excitons localization, higher energy barrier for nonradiative recombination of carriers with dislocations and the reduction in defect density of the materials grown on the nanoporous GaN template. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3005409]