Sub-micron InGaN Ring Structures for High-efficiency LEDs
|Hoi Wai Choi 1, Paul R. Edwards 2, Chan-wook Jeon 1, Robert W. Martin 2, Martin D. Dawson 1, Sudhiranjan Tripathy 3, Soo Jin Chua 3|
1. University of Strathclyde, Institute of Photonics (IOP), Wolfson Centre, 106 Rottenrow, Glasgow G4 0NW, United Kingdom
Various forms of the InGaN micro-LED concept have been reported in recent years, all of which indicate that an enhanced efficiency can be achieved with such microstructures. The overall external quantum efficiency of an InGaN LED is heavily dependent on the internal quantum efficiency (which is limited by the build-in piezoelectric field) and the extraction efficiency (due to the high refractive index of nitride materials). A significant increase in extraction efficiency is certainly achieved in the current generation of micro-LEDs, where the dimension of an individual element of typically larger than 4mm. However, in order to achieve a reduction of the piezoelectric field in the InGaN quantum wells, the dimension of the micro-LED should be further reduced. In fact, Demangeot et al observed significant strain relaxation in InGaN microstructures of less than 1 μ m through micro-Raman scattering, suggesting that micro-LEDs should be scaled down to sub-micron dimensions in order to benefit from an increased in internal quantum efficiency.
Presentation: oral at E-MRS Fall Meeting 2003, Symposium A, by Hoi Wai Choi
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-05-07 16:06 Revised: 2009-06-08 12:55