Document Type

Article

Publication Date

2017

Abstract

The gallium vacancy, an intrinsic acceptor, is identified in β-Ga2O3 using electron paramagnetic resonance (EPR). Spectra from doubly ionized (V2−Ga) and singly ionized (VGa) gallium vacancies are observed at room temperature, without photoexcitation, after an irradiation with high-energy neutrons. The V2−Ga centers (with S = 1/2) have a slight angular variation due to a small anisotropy in the g matrix (principal values are 2.0034, 2.0097, and 2.0322). The V2−Ga centers also exhibit a resolved hyperfine structure due to equal and nearly isotropic interactions with the 69,71Ga nuclei at two Ga sites (the hyperfine parameters are 1.28 and 1.63 mT for the 69Ga and 71Ga nuclei, respectively, when the field is along the a direction). Based on these g-matrix and hyperfine results, the model for the ground state of the doubly ionized vacancy (V2−Ga) has a hole localized on one threefold-coordinated oxygen ion. The vacancy is located at one of the three neighboring gallium sites, and the remaining two gallium neighbors are responsible for the equal hyperfine interactions. The singly ionized (VGa) gallium vacancies are also paramagnetic. In this latter acceptor, the two holes are localized on separate oxygen ions adjacent to one gallium vacancy. Their spins align parallel to give a triplet S = 1 EPR spectrum with resolved hyperfine structure from interactions with gallium neighbors.

Comments

This record sources the open access CHORUS-furnished accepted manuscript (post-print) version of the article. A 12-month embargo was observed for this posting in accordance with the publisher and the research funding body.

The publisher version of record is a subscription-access article. Readers outside of AFIT will need to access the article through their own digital subscription to that periodical. AFIT readers can reach the final article through AFIT Off-Campus Access.

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett 110, 202104 (2017) and may be found at https://doi.org/10.1063/1.4983814.

DOI

10.1063/1.4983814

Source Publication

Applied Physics Letters

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