Identification of acceptor states in Li-doped p-type ZnO thin films.

Authors :: Zeng, Y. J.
Ye, Z. Z.
Lu, J. G.
Xu, W. Z.
Zhu, L. P.
Zhao, B. H.
Sukit Limpijumnong
Source :: Applied Physics Letters; 7/24/2006, Vol. 89 Issue 4, p042106, 3p, 1 Chart, 3 Graphs
Publication Year :: 2006
Abstract: We investigate photoluminescence from reproducible Li-doped p-type ZnO thin films prepared by dc reactive magnetron sputtering. The Li<subscript>Zn</subscript> acceptor state, with an energy level located at 150 meV above the valence band maximum, is identified from free-to-neutral-acceptor transitions. Another deeper acceptor state located at 250 meV emerges with the increased Li concentration. A broad emission centered at 2.96 eV is attributed to a donor-acceptor pair recombination involving zinc vacancy. In addition, two chemical bonding states of Li, evident in x-ray photoelectron spectroscopy, are probably associated with the two acceptor states observed. [ABSTRACT FROM AUTHOR]