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Nanoscale Characterization of V-Defect in InGaN/GaN QWs LEDs Using Near-Field Scanning Optical Microscopy

Authors :
Yufeng Li
Weihan Tang
Ye Zhang
Maofeng Guo
Qiang Li
Xilin Su
Aixing Li
Feng Yun
Source :
Nanomaterials, Vol 9, Iss 4, p 633 (2019)
Publication Year :
2019
Publisher :
MDPI AG, 2019.

Abstract

The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by near-field scanning optical microscopy. The current distribution along the {10-11} facets of the large defect was measured by conductive atomic force microscopy. Nearly 20 times the current injection and dominant emission from bottom quantum wells were found in the V-defect compared to its vicinity. Such enhanced current injection into the bottom part of quantum wells through V-defect results in higher light output power. Reduced external quantum efficiency droops were achieved due to more uniform carrier distribution. The un-encapsulated fabricated chip shows light output power of 172.5 mW and 201.7 mW at 400 mA, and external quantum efficiency drop of 22.3% and 15.4% for the sample without and with large V-defects, respectively. Modified V-defects provide a simple and effective approach to suppress the efficiency droop problem that occurs at high current injection, while improving overall quantum efficiency.

Details

Language :
English
ISSN :
20794991
Volume :
9
Issue :
4
Database :
Directory of Open Access Journals
Journal :
Nanomaterials
Publication Type :
Academic Journal
Accession number :
edsdoj.8d643d980ca9462aa5d91b017af5a048
Document Type :
article
Full Text :
https://doi.org/10.3390/nano9040633