Document Type


Original Publication Date


Journal/Book/Conference Title

Applied Physics Letters





DOI of Original Publication



Originally published at

Date of Submission

April 2015


The internal quantum efficiency(IQE) and relative external quantum efficiency (EQE) in InGaNlight-emitting diodes(LEDs) emitting at 400 nm with and without electron blocking layers (EBLs) on c-plane GaN and m-plane GaN were investigated in order to shed some light on any effect of polarizationcharge induced field on efficiency killer carrier spillover. Without an EBL the EQE values suffered considerably (by 80%) for both orientations, which is clearly attributable to carrier spillover. Substantial carrier spillover in both polarities, therefore, suggests that the polarizationcharge is not the major factor in efficiency degradation observed, particularly at high injection levels. Furthermore, the m-plane variety with EBL did not show any discernable efficiency degradation up to a maximum current density of 2250 A cm−2 employed while that on c-plane showed a reduction by ∼40%. In addition, IQE of m-plane LED structure determined from excitation power dependent photoluminescence was ∼80% compared to 50% in c-plane LEDs under resonant and moderate excitation condition. This too is indicative of the superiority of m-plane LED structures, most probably due to relatively larger optical matrix elements for m-plane orientation.


Lee, J., Li, X., Ni, X., et al. On carrier spillover in c- and m-plane InGaN light emitting diodes. Applied Physics Letters, 95, 201113 (2009). Copyright © 2009 AIP Publishing LLC.

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VCU Electrical and Computer Engineering Publications