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Eljarrat A, Sastre X, Peiró F, et al. Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys. Microsc Microanal. 2016;22(3):706-16doi: 10.1017/S1431927616000106.
Eljarrat, A., Sastre, X., Peiró, F., & Estradé, S. (2016). Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, 22(3), 706-16. https://doi.org/10.1017/S1431927616000106
Eljarrat, Alberto, et al. "Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys." Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada vol. 22,3 (2016): 706-16. doi: https://doi.org/10.1017/S1431927616000106
Eljarrat A, Sastre X, Peiró F, Estradé S. Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys. Microsc Microanal. 2016 Jun;22(3):706-16. doi: 10.1017/S1431927616000106. Epub 2016 Feb 12. PMID: 26868876.
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Microsc Microanal. 2016 Jun;22(3):706-16. doi: 10.1017/S1431927616000106. Epub 2016 Feb 12.

Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys.

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada

Alberto Eljarrat, Xavier Sastre, Francesca Peiró, Sónia Estradé

Affiliations

  1. Laboratory of Electron NanoScopies,LENS-MIND-IN2UB,Departament d'Electr?nica,Universitat de Barcelona,Marti i Franqués 1,08028 Barcelona,Spain.

PMID: 26868876 DOI: 10.1017/S1431927616000106

Abstract

In the present work, the dielectric response of III-nitride semiconductors is studied using density functional theory (DFT) band structure calculations. The aim of this study is to improve our understanding of the features in the low-loss electron energy-loss spectra of ternary alloys, but the results are also relevant to optical and UV spectroscopy results. In addition, the dependence of the most remarkable features with composition is tested, i.e. applying Vegard's law to band gap and plasmon energy. For this purpose, three wurtzite ternary alloys, from the combination of binaries AlN, GaN, and InN, were simulated through a wide compositional range (i.e., Al x Ga1-x N, In x Al1-x N, and In x Ga1-x N, with x=[0,1]). For this DFT calculations, the standard tools found in Wien2k software were used. In order to improve the band structure description of these semiconductor compounds, the modified Becke-Johnson exchange-correlation potential was also used. Results from these calculations are presented, including band structure, density of states, and complex dielectric function for the whole compositional range. Larger, closer to experimental values, band gap energies are predicted using the novel potential, when compared with standard generalized gradient approximation. Moreover, a detailed analysis of the collective excitation features in the dielectric response reveals their compositional dependence, which sometimes departs from a linear behavior (bowing). Finally, an advantageous method for measuring the plasmon energy dependence from these calculations is explained.

Keywords: EELS; III-V semiconductors; Plasmon; Vegard’s law; band gap

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