posted on 2013-05-30, 00:00authored byXingyi Deng, Kun Yao, Keju Sun, Wei-Xue Li, Junseok Lee, Christopher Matranga
The stoichiometric single- and bilayer
ZnO(0001) have been prepared
by reactive deposition of Zn on Au(111) and studied in detail with
X-ray photoelectron spectroscopy, scanning tunneling microscopy, and
density functional theory calculations. Both single- and bilayer ZnO(0001)
adopt a planar, graphite-like structure similar to freestanding ZnO(0001)
due to the weak van der Waals interactions dominating their adhesion
with the Au(111) substrate. At higher temperature, the single-layer
ZnO(0001) converts gradually to bilayer ZnO(0001) due to the twice
stronger interaction between two ZnO layers than the interfacial adhesion
of ZnO with Au substrate. It is found that Cu atoms on the surface
of bilayer ZnO(0001) are mobile with a diffusion barrier of 0.31 eV
and likely to agglomerate and form nanosized particles at low coverages;
while Cu atoms tend to penetrate a single layer of ZnO(0001) with
a barrier of 0.10 eV, resulting in a Cu free surface.