Document Type

Article

Publication Date

4-2016

Abstract

An electron paramagnetic resonance (EPR) spectrum in neutron-irradiated ZnO crystals is assigned to the zinc-oxygen divacancy. These divacancies are observed in the bulk of both hydrothermally grown and seeded-chemical-vapor-transport-grown crystals after irradiations with fast neutrons. Neutral nonparamagnetic complexes consisting of adjacent zinc and oxygen vacancies are formed during the irradiation. Subsequent illumination below ∼150 K with 442 nm laser light converts these (V2−Zn − V2+O)0 defects to their EPR-active state (VZn − V2+O)+ as electrons are transferred to donors. The resulting photoinduced S = 1/2 spectrum of the divacancy is holelike and has a well-resolved angular dependence from which a complete g matrix is obtained. Principal values of the g matrix are 2.00796, 2.00480, and 2.00244. The unpaired spin resides primarily on one of the three remaining oxygen ions immediately adjacent to the zinc vacancy, thus making the electronic structure of the (V−Zn − V2+O)+ ground state similar to the isolated singly ionized axial zinc vacancy. The neutral (V2−Zn − V2+O)0 divacancies dissociate when the ZnO crystals are heated above 250 °C. After heating above this temperature, the divacancy EPR signal cannot be regenerated at low temperature with light.

Comments

A 12-month embargo was observed before posting, in accordance with AIP policy. Sourced from the version of record as cited below.
© 2016 AIP Publishing LLC. 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 Journal of Applied Physics, 119, 145701 (2016) and may be found at https://doi.org/10.1063/1.4945703.

DOI

10.1063/1.4945703

Source Publication

Journal of Applied Physics

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