On the impact of indium distribution on the electronic properties in InGaN nanodisks

We analyze an epitaxially grown heterostructure composed of InGaN nanodisks inserted in GaN nanowires in order to relate indium concentration to the electronic properties. This study was achieved with spatially resolved low-loss electron energy-loss spectroscopy using monochromated electrons to prob...

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Bibliographic Details
Published in:Applied physics letters 2015-03, Vol.106 (10)
Main Authors: Benaissa, M., Sigle, W., Ng, T. K., El Bouayadi, R., van Aken, P. A., Jahangir, S., Bhattacharya, P., Ooi, B. S.
Format: Article
Language:English
Subjects:
Applied physics
Composition
CONCENTRATION RATIO
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
DIELECTRIC MATERIALS
Electron energy
Electron energy loss spectroscopy
ELECTRONIC STRUCTURE
ELECTRONS
EMISSION
Emission analysis
ENERGY-LOSS SPECTROSCOPY
Epitaxial growth
EPITAXY
FLUCTUATIONS
GALLIUM NITRIDES
Heterostructures
Indium
INDIUM COMPOUNDS
Indium gallium nitrides
INTERFACES
NANOSCIENCE AND NANOTECHNOLOGY
NANOWIRES
OPTICAL PROPERTIES
PLASMONS
Variation
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Summary:We analyze an epitaxially grown heterostructure composed of InGaN nanodisks inserted in GaN nanowires in order to relate indium concentration to the electronic properties. This study was achieved with spatially resolved low-loss electron energy-loss spectroscopy using monochromated electrons to probe optical excitations—plasmons—at nanometer scale. Our findings show that each nanowire has its own indium fluctuation and therefore its own average composition. Due to this indium distribution, a scatter is obtained in plasmon energies, and therefore in the optical dielectric function, of the nanowire ensemble. We suppose that these inhomogeneous electronic properties significantly alter band-to-band transitions and consequently induce emission broadening. In addition, the observation of tailing indium composition into the GaN barrier suggests a graded well-barrier interface leading to further inhomogeneous broadening of the electro-optical properties. An improvement in the indium incorporation during growth is therefore needed to narrow the emission linewidth of the presently studied heterostructures.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4915117