Open AccessAnomalous electroluminescent blue-shift behavior induced by well widths variance and localization effect in InGaN/GaN multi-quantum wells
Author(s) -
Liyuan Peng,
Danyun Zhao,
Desheng Jiang,
Jianjun Zhu,
Zongshun Liu,
Ping Chen,
Jing Yang,
Wei Liu,
Feng Liang,
Yufeng Xing,
Shuangtao Liu,
Liqun Zhang,
Wenjie Wang,
Mo Li,
Yuantao Zhang,
Guotong Du
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.021736
Subject(s) - electroluminescence , materials science , metalorganic vapour phase epitaxy , blueshift , photoluminescence , homogeneity (statistics) , chemical vapor deposition , optoelectronics , quantum well , light emitting diode , optics , layer (electronics) , laser , nanotechnology , physics , epitaxy , statistics , mathematics
Twelve InGaN MQW LED samples with varying well thickness grown via metal-organic chemical vaper deposition (MOCVD) are investigated. It is observed from electroluminescence (EL) measurement that at low current densities, the peak energy shifts to blue with increasing current, and when the current change by fixed increment, the peak energy shifts to blue end to different extent among samples. This blue shift was expected to be stronger when the well thickness increases, however, for well widths above 5 nm we observe a decrease in emission energy. Since no relaxation was detected from reciprocal space mapping (RSM), the deteriorated homogeneity is found to be responsible for this phenomenon. Temperature dependent photoluminescence (TDPL) results analyzed by band-tail model fitting show that the localization effect gets more prominent with increasing well thickness. It is found that elevating the growth temperature of active region from 710°C to 750°C significantly improves the homogeneity of InGaN layer.