Determining GaN nanowire polarity and its influence on light emission in the scanning electron microscope
Naresh-Kumar, G. and Bruckbauer, J. and Winkelmann, A. and Yu, X. and Hourahine, B. and Edwards, P. R. and Wang, T. and Trager-Cowan, C. and Martin, R. W. (2019) Determining GaN nanowire polarity and its influence on light emission in the scanning electron microscope. Nano Letters, 19 (6). pp. 3863-3870. ISSN 1530-6992 (https://doi.org/10.1021/acs.nanolett.9b01054)
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Abstract
The crystal polarity of non-centrosymmetric wurtzite GaN nanowires is determined non-destructively 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 non-centrosymmetric crystals by interrogating differences in the intensity distribution of bands of the EBSD pattern associated with semi-polar 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 measureable shift (≈28 meV) in the 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 non-destructively identify polarity in a wide range of non-centrosymmetric nanoscale material systems and provide direct comparison with their luminescence.
ORCID iDs
Naresh-Kumar, G. ORCID: https://orcid.org/0000-0002-9642-8137, Bruckbauer, J. ORCID: https://orcid.org/0000-0001-9236-9320, Winkelmann, A., Yu, X., Hourahine, B. ORCID: https://orcid.org/0000-0002-7667-7101, Edwards, P. R. ORCID: https://orcid.org/0000-0001-7671-7698, Wang, T., Trager-Cowan, C. ORCID: https://orcid.org/0000-0001-8684-7410 and Martin, R. W. ORCID: https://orcid.org/0000-0002-6119-764X;-
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Item type: Article ID code: 67670 Dates: DateEvent12 June 2019Published30 April 2019Published Online23 April 2019Accepted13 March 2019SubmittedSubjects: Science > Physics Department: Faculty of Science > Physics
Strategic Research Themes > Measurement Science and Enabling TechnologiesDepositing user: Pure Administrator Date deposited: 01 May 2019 15:52 Last modified: 01 Oct 2024 09:11 URI: https://strathprints.strath.ac.uk/id/eprint/67670