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標題: Efficiency improvement of near-ultraviolet InGaN LEDs using patterned sapphire substrates
作者: Wang, W.K.
Wuu, D.S.
Lin, S.H.
Han, P.
Horng, R.H.
Hsu, T.C.
Huo, D.T.C.
Jou, M.J.
Yu, Y.H.
Lin, A.K.
韓 斌
關鍵字: GaN;InGaN;light-emitting diode (LED);near ultraviolet (UV);patterned;sapphire substrate (PSS);light-emitting-diodes;output power;epitaxy;layers
Project: Ieee Journal of Quantum Electronics
期刊/報告no:: Ieee Journal of Quantum Electronics, Volume 41, Issue 11, Page(s) 1403-1409.
The use of conventional and patterned sapphire substrates (PSSs) to fabricate InGaN-based near-ultraviolet (410 nm) light-emitting diodes (LEDs) was demonstrated. The PSS was prepared using a periodic hole pattern (diameter: 3 pro; spacing: 3 mu m) on the (0001) sapphire with different etching depths. From transmission-electron-microscopy and etch-pit-density studies, the PSS with an optimum pattern depth (D-h = 1.5 mu m) was confirmed to be an efficient way to reduce the thread dislocations in the GaN microstructure. It was found that the output power increased from 8.6 to 10.4 mW, corresponding to about 29% increases in the external quantum efficiency. However, the internal quantum efficiency (@ 20 mA) was about 36% and 38% for the conventional and PSS LEDs, respectively. The achieved improvement of the output power is not only due to the improvement of the internal quantum efficiency upon decreasing the dislocation density, but also due to the enhancement of the extraction efficiency using the PSS. Finally, better long-time reliability of the PSS LED performance was observed.
ISSN: 0018-9197
DOI: 10.1109/jqe.2005.857057
Appears in Collections:材料科學與工程學系

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