Open AccessEfficiency droop in blue InGaN/GaN light emitting diodes on Si substrate
Author(s) -
Mulin Liu,
Min Qiu-Ying,
Zhiqing Ye
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.178503
Subject(s) - voltage droop , materials science , optoelectronics , diode , light emitting diode , auger effect , electroluminescence , quantum efficiency , leakage (economics) , electron , indium gallium nitride , gallium nitride , physics , nanotechnology , voltage , layer (electronics) , quantum mechanics , economics , macroeconomics , voltage divider
InGaN/GaN based light emitting diodes (LEDs) suffer from decrease in efficiency at a high injection current level which is called efficiency droop. In this paper, blue InGaN/GaN multiple quantum well light emitting diodes on Si (111) substrates are prepared, and their electroluminescence spectra are tested. Comparing the experimental measurements with the simulating results based on simple ABC model, the cause for quantum efficiency droop is investigated. The results show that the light emitting diode has worse electron spreading and less hole concentration with temperature decreasing, and the electrons will overflow frome the well after filled up in higher and higher state for their inhomogeneous distribution, thus efficiency droop will happen at a lower injection more severely for electron leakage under lower injection, and experimental measurements are in disagreement with simulation results of Auger recombination at high injection current levels under different temperatures. The results confirm that the main factor for efficiency droop is not Auger nonradiative recombination but electron leakage, and the essential cause for electron leakage is severe carrier localization.