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 LiZn 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]