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Defect‐enabled electrical current leakage in ultraviolet light‐emitting diodes (Phys. Status Solidi A 4∕2015)
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.201570422
Subject(s) - materials science , optoelectronics , ultraviolet , leakage (economics) , diode , light emitting diode , conductive atomic force microscopy , chemical vapor deposition , ultraviolet light , nanotechnology , atomic force microscopy , macroeconomics , economics
The AlGaN materials system offers a tunable, ultra‐wide bandgap that is exceptionally useful for high‐power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726 ) investigate a structural defect known as an open‐core threading dislocation or “nanopipe” that is particularly detrimental to devices that employ these materials. An AlGaN thin film was synthesized using metal‐organic chemical‐vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic‐force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, and the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. With this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light‐emitting diode optical output power with increasing nanopipe density.