Formation of Isolated Zn Vacancies in ZnO Single Crystals by Absorption of Ultraviolet Radiation: A Combined Study Using Positron Annihilation, Photoluminescence, and Mass Spectroscopy

Enamul H. Khan, Marc H. Weber, and Matthew D. McCluskey

Phys. Rev. Lett. 111, 017401 – Published 2 July 2013

Abstract

Positron annihilation spectra reveal isolated zinc vacancy ( $V_{Zn}$ ) creation in single-crystal ZnO exposed to 193-nm radiation at $100 mJ / {cm}^{2}$ fluence. The appearance of a photoluminescence excitation peak at 3.18 eV in irradiated ZnO is attributed to an electronic transition from the $V_{Zn}$ acceptor level at $\sim 100 meV$ to the conduction band. The observed $V_{Zn}$ density profile and hyperthermal ${Zn}^{+}$ ion emission support zinc vacancy-interstitial Frenkel pair creation by exciting a wide 6.34 eV Zn-O antibonding state at 193-nm photon—a novel photoelectronic process for controlled $V_{Zn}$ creation in ZnO.

Received 4 February 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.017401

Authors & Affiliations

Enamul H. Khan^1,*, Marc H. Weber², and Matthew D. McCluskey¹

¹Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
²Center for Materials Research, Washington State University, Pullman, Washington 99164-2711, USA