Naresh-Kumar, G., Bruckbauer, J., Winkelmann, A. et al. (6 more authors) (2019) Determining GaN nanowire polarity and its influence on light emission in the scanning electron microscope. Nano Letters, 19 (6). pp. 3863-3870. ISSN 1530-6984
Abstract
The crystal polarity of noncentrosymmetric wurtzite GaN nanowires is determined nondestructively in the scanning electron microscope using electron backscatter diffraction (EBSD). The impact of the nanowire polarity on light emission is then investigated using cathodoluminescence (CL) spectroscopy. EBSD can determine polarity of noncentrosymmetric crystals by interrogating differences in the intensity distribution of bands of the EBSD pattern associated with semipolar planes. Experimental EBSD patterns from an array of GaN nanowires are compared with theoretical patterns produced using dynamical electron simulations to reveal whether they are Ga- or N-polar or, as in several cases, of mixed polarity. CL spectroscopy demonstrates the effect of the polarity on light emission, with spectra obtained from nanowires of known polarity revealing a small but measurable shift (≈28 meV) in the GaN near band edge emission energy between those with Ga and N polarity. We attributed this energy shift to a difference in impurity incorporation in nanowires of different crystal polarity. This approach can be employed to nondestructively identify polarity in a wide range of noncentrosymmetric nanoscale material systems and provide direct comparison with their luminescence.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, (https://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
Keywords: | Nanowires; polarity; electron diffraction; SEM; GaN; cathodoluminescence |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Electronic and Electrical Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/M015181/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/P006973/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 22 Apr 2020 09:19 |
Last Modified: | 22 Apr 2020 23:33 |
Status: | Published |
Publisher: | American Chemical Society (ACS) |
Refereed: | Yes |
Identification Number: | 10.1021/acs.nanolett.9b01054 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:159175 |