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Defect‐enabled electrical current leakage in ultraviolet light‐emitting diodes
Author(s) -
Moseley Michael W.,
Allerman Andrew A.,
Crawford Mary H.,
Wierer Jonathan J.,
Smith Michael L.,
Biedermann Laura B.
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201400182
Subject(s) - materials science , light emitting diode , optoelectronics , ultraviolet , dislocation , diode , conductive atomic force microscopy , threading (protein sequence) , leakage (economics) , atomic force microscopy , nanotechnology , composite material , chemistry , biochemistry , protein structure , economics , macroeconomics
Electrical current leakage paths in AlGaN‐based ultraviolet (UV) light‐emitting diodes (LEDs) are identified using conductive atomic force microscopy. Open‐core threading dislocations are found to conduct current through insulating Al 0.7 Ga 0.3 N layers. A defect‐sensitive H 3 PO 4 etch reveals these open‐core threading dislocations as 1–2 µm wide hexagonal etch pits visible with optical microscopy. Additionally, closed‐core threading dislocations are decorated with smaller and more numerous nanometer‐scale pits, which are quantifiable by atomic‐force microscopy. The performances of UV‐LEDs fabricated on similar Si‐doped Al 0.7 Ga 0.3 N templates are found to have a strong correlation to the density of these electrically conductive open‐core dislocations, while the total threading dislocation densities of the UV‐LEDs remain relatively unchanged.