Investigating the origin of efficiency droop by profiling the temperature across the multi-quantum well of an operating light-emitting diode

Euihan Jung, Gwangseok Hwang, Jaehun Chung, Oh Myoung Kwon, Jaecheon Han, Yong Tae Moon, Tae Yeon Seong

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9 Citations (Scopus)

Abstract

Performance degradation resulting from efficiency droop during high-power operation is a critical problem in the development of high-efficiency light-emitting diodes (LEDs). In order to resolve the efficiency droop and increase the external quantum efficiency of LEDs, the droop's origin should be identified first. To experimentally investigate the cause of efficiency droop, we used null-point scanning thermal microscopy to quantitatively profile the temperature distribution on the cross section of the epi-layers of an operating GaN-based vertical LED with nanoscale spatial resolution at four different current densities. The movement of temperature peak towards the p-GaN side as the current density increases suggests that more heat is generated by leakage current than by Auger recombination. We therefore suspect that at higher current densities, current leakage becomes the dominant cause of the droop problem.

Original languageEnglish
Article number041114
JournalApplied Physics Letters
Volume106
Issue number4
DOIs
Publication statusPublished - 2015 Jan 26

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ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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