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Title: Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures

Abstract

We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c− polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.

Authors:
; ; ; ; ; ; ;  [1]
  1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
Publication Date:
OSTI Identifier:
22275604
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 115; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; CATIONS; COMPARATIVE EVALUATIONS; CRYSTALS; CUBIC LATTICES; EPITAXY; GALLIUM NITRIDES; LAYERS; MAGNESIUM OXIDES; SAPPHIRE; THIN FILMS; X RADIATION; X-RAY DIFFRACTION; ZINC OXIDES

Citation Formats

Shelton, Christopher T., Sachet, Edward, Paisley, Elizabeth A., Hoffmann, Marc P., Rajan, Joseph, Collazo, Ramón, Sitar, Zlatko, and Maria, Jon-Paul. Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures. United States: N. p., 2014. Web. doi:10.1063/1.4863120.
Shelton, Christopher T., Sachet, Edward, Paisley, Elizabeth A., Hoffmann, Marc P., Rajan, Joseph, Collazo, Ramón, Sitar, Zlatko, & Maria, Jon-Paul. Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures. United States. https://doi.org/10.1063/1.4863120
Shelton, Christopher T., Sachet, Edward, Paisley, Elizabeth A., Hoffmann, Marc P., Rajan, Joseph, Collazo, Ramón, Sitar, Zlatko, and Maria, Jon-Paul. 2014. "Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures". United States. https://doi.org/10.1063/1.4863120.
@article{osti_22275604,
title = {Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures},
author = {Shelton, Christopher T. and Sachet, Edward and Paisley, Elizabeth A. and Hoffmann, Marc P. and Rajan, Joseph and Collazo, Ramón and Sitar, Zlatko and Maria, Jon-Paul},
abstractNote = {We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c− polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.},
doi = {10.1063/1.4863120},
url = {https://www.osti.gov/biblio/22275604}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 4,
volume = 115,
place = {United States},
year = {Tue Jan 28 00:00:00 EST 2014},
month = {Tue Jan 28 00:00:00 EST 2014}
}