Defect-reduced green GaInN/GaN light-emitting diode on nanopatterned sapphire

Future Chips Constellation, Rensselaer Polytechnic Institute, Troy, New York 12180, USA and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
Applied Physics Letters (Impact Factor: 3.52). 01/2011; 98. DOI: 10.1063/1.3579255
Source: IEEE Xplore

ABSTRACT Green GaInN/GaN quantum well light-emitting diode (LED) wafers were grown on nanopatterned c-plane sapphire substrate by metal-organic vapor phase epitaxy. Without roughening the chip surface, such LEDs show triple the light output over structures on planar sapphire. By quantitative analysis the enhancement was attributed to both, enhanced generation efficiency and extraction. The spectral interference and emission patterns reveal a 58% enhanced light extraction while photoluminescence reveals a doubling of the internal quantum efficiency. The latter was attributed to a 44% lower threading dislocation density as observed in transmission electron microscopy. The partial light output power measured from the sapphire side of the unencapsulated nanopatterned substrate LED die reaches 5.2 mW at 525 nm at 100 mA compared to 1.8 mW in the reference LED. (C) 2011 American Institute of Physics. [doi:10.1063/1.3579255]

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