Identification of substitutional Li in n-type ZnO and its role as an acceptor

Loading...
Thumbnail Image

Access rights

openAccess
publishedVersion

URL

Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Major/Subject

Mcode

Degree programme

Language

en

Pages

7

Series

Physical Review B, Volume 83, issue 24, pp. 1-7

Abstract

Monocrystalline n-type zinc oxide (ZnO) samples prepared by different techniques and containing various amounts of lithium (Li) have been studied by positron annihilation spectroscopy (PAS) and secondary ion mass spectrometry. A distinct PAS signature of negatively charged Li atoms occupying a Zn-site (Li−Zn), so-called substitutional Li, is identified and thus enables a quantitative determination of the content of LiZn. In hydrothermally grown samples with a total Li concentration of ~2×1017cm−3,LiZn is found to prevail strongly, with only minor influence, by other possible configurations of Li. Also in melt grown samples doped with Li to a total concentration as high as 1.5×1019cm−3, a considerable fraction of the Li atoms (at least 20%) is shown to reside on the Zn-site, but despite the corresponding absolute acceptor concentration of ⩾(2–3)×1018cm−3, the samples did not exhibit any detectable p-type conductivity. The presence of LiZn is demonstrated to account for the systematic difference in positron lifetime of 10–15 ps between Li-rich and Li-lean ZnO materials as found in the literature, but further work is needed to fully elucidate the role of residual hydrogen impurities and intrinsic open volume defects.

Description

Other note

Citation

Johansen, K M, Zubiaga, A, Makkonen, I, Tuomisto, F, Neuvonen, P T, Knutsen, K E, Monakhov, E V, Kuznetsov, A Y & Svensson, B G 2011, 'Identification of substitutional Li in n-type ZnO and its role as an acceptor', Physical Review B, vol. 83, no. 24, 245208, pp. 1-7. https://doi.org/10.1103/PhysRevB.83.245208