Influences of screw dislocations on electroluminescence of AlGaN/AlN-based UVC LEDs

We investigated two types of threading dislocations in high Al-composition Al0.55Ga0.45N/AlN multiple quantum well (MQW) structures grown on AlN substrate for electrically injected deep ultraviolet light-emitting diodes (LEDs). The surface morphology and defects electrical characteristics of the MQW...

Full description

Saved in:
Bibliographic Details
Published in:AIP advances 2019-08, Vol.9 (8), p.085128-085128-6
Main Authors: Liu, Dong, Cho, Sang June, Zhang, Huilong, Carlos, Corey R., Kalapala, Akhil R. K., Park, Jeongpil, Kim, Jisoo, Dalmau, Rafael, Gong, Jiarui, Moody, Baxter, Wang, Xudong, Albrecht, John D., Zhou, Weidong, Ma, Zhenqiang
Format: Article
Language:English
Subjects:
Aluminum gallium nitrides
Atomic force microscopy
Composition
Current leakage
Diodes
Electroluminescence
Emission spectra
Inhomogeneity
Light emission
Morphology
Organic light emitting diodes
Photoluminescence
Quantum wells
Screw dislocations
Substrates
Threading dislocations
Ultraviolet radiation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We investigated two types of threading dislocations in high Al-composition Al0.55Ga0.45N/AlN multiple quantum well (MQW) structures grown on AlN substrate for electrically injected deep ultraviolet light-emitting diodes (LEDs). The surface morphology and defects electrical characteristics of the MQW LED structures were examined via conductive atomic force microscopy (CAFM). We found that the disparity between photoluminescence (PL) and electroluminescence (EL) spectra in terms of light emission output and wavelength shift are attributed to the existence of the surface hillocks, especially to the ones that have open-core dislocations. The open-core dislocations form current leakage paths through their defect states and the composition inhomogeneity (i.e., Ga rich) at the dislocation sites are responsible for the light emission at longer wavelengths.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.5108743