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Proceedings Paper

Cubic ZnMgO alloys for deep ultraviolet applications (Conference Presentation)
Author(s): Henryk Teisseyre; Izabella Gorczyca; Dawid Jarosz; Małgorzata Wierzbowska; Sławomir Kret; Fabrice Donatini; Daniel Le Si Dang

Paper Abstract

Cubic ZnxMg1-xO have been proposed as wide bandgap semiconductors for short wavelength optoelectronic applications operating in the deep UV region. By combing MBE growth and HRTEM we were able to determine conditions in which ZnO and ZnxMg1-xO alloys in the rocksalt phase can be grown on MgO substrates. It was found that the maximum ZnxMg1-xO layer thickness strongly depends on Zn concentration, decreasing with x, which reflects the alloy phase instability. The band structures of rocksalt ZnxMg1-xO alloys were calculated in a supercell geometry by density functional theory in the Local Density Approximation (LDA). The atomic coordinates were determined using pseudopotentials implemented in the VASP Simulation Package. Then, the band structures were obtained by a Linear-Muffin-Tin-Orbital method in a full-potential version with a semi-empirical correction (LDA+C) for the band gaps. As MgO in the rocksalt structure has a direct band gap and ZnO has an indirect one, we expected transition: direct to the indirect gap for a certain content, x, of Zn. However, it is shown, that the ZnxMg1-xO band gaps depend strongly on the local arrangement of atoms in a 64 atoms supercell. For each concentration of Zn we obtained a set of the band gap values depending on the arrangement of atoms. Instead of two crossing lines illustrating the dependence of the direct and indirect gaps on composition, we got two crossing bands. The crossing of the two bands covers composition from 10% of Zn up to almost 70% of Zn. The results are compared with the experimental data.

Paper Details

Date Published: 8 March 2019
Proc. SPIE 10919, Oxide-based Materials and Devices X, 1091915 (8 March 2019); doi: 10.1117/12.2516975
Show Author Affiliations
Henryk Teisseyre, Institute of Physics, PAS (Poland)
Izabella Gorczyca, Institute of High Pressure Physics (Poland)
Dawid Jarosz, Institute of Physics, PAS (Poland)
Małgorzata Wierzbowska, Institute of High Pressure Physics (Poland)
Sławomir Kret, Institute of Physics, PAS (Poland)
Fabrice Donatini, Institut NÉEL (France)
Daniel Le Si Dang, Institut NÉEL (France)

Published in SPIE Proceedings Vol. 10919:
Oxide-based Materials and Devices X
David J. Rogers; David C. Look; Ferechteh H. Teherani, Editor(s)

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