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Improved quality nonpolar a-plane GaN/AlGaN UV LEDs grown with sidewall lateral epitaxial overgrowth (SLEO)

İmer, Muhsine Bilge
Schmidt, Matt
Haskell, Ben
Rajan, Siddharth
Zhong, Barry
Kim, Kwangchoong
Wu, Feng
Mates, Tom
Keller, Stacia
Mishra, Umesh K.
Nakamura, Shuji
Speck, James S.
DenBaars, Steven P.
High quality nonpolar a-plane GaN templates were grown by utilizing sidewall lateral epitaxial overgrowth (SLEO) technique with threading dislocation density of similar to 10(6)-10(7) cm(-2). 360 run GaN/AlGaN multiple quantum well ultraviolet light emitting diodes were grown with metalorganic chemical vapor deposition. Reduced defect density SLEO a-plane, planar a-plane, and planar c-plane templates were co-loaded for device growth and processed together in order to make relative device performance comparison. For SLEO a-plane LEDs EL peak position was measured at 360 nm and it was independent of drive current, The linewidth of the emission was 7 nm. The series resistance of these diodes was as low as 16,5 0 and the forward voltage was measured as 4.08 V at 20 mA. The external quantum efficiency of the high quality SLEO a-plane devices was similar to 275x higher than planar a-plane devices. The highest output power was realized at 200 mA as 65 mu W. The effect of contact geometry on electrical and optical characteristics of the devices was also discussed.