InGaN nano-ring structures for high-efficiency light emitting diodes

Choi, H. W. and Jeon, C. W. and Liu, C. and Watson, I. M. and Dawson, M. D. and Edwards, P. R. and Martin, R. W. and Tripathy, S. and Chua, S. J. (2004) InGaN nano-ring structures for high-efficiency light emitting diodes. Applied Physics Letters, 86 (2). 021101. ISSN 0003-6951 (

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A technique based on the Fresnel diffraction effect for the fabrication of nano-scale site-controlled ring structures in InGaN/GaN multi-quantum well structures has been demonstrated. The ring structures have an internal diameter of 500 nm and a wall width of 300 nm. A 1 cm-1 Raman shift has been measured, signifying substantial strain relaxation from the fabricated structure. The 9 nm blueshift observed in the cathodoluminescence spectra can be attributed to band filling and/or screening of the piezoelectric field. A light emitting diode based on this geometry has been demonstrated.