The presence of a (1 × 1) oxygen overlayer on ZnO(0001) surfaces and at Schottky interfaces.
The atomic surface and interface structures of uncoated and metal-coated epi-polished ZnO(0001) Zn-polar wafers were investigated via surface x-ray diffraction. All uncoated samples showed the presence of a fully occupied (1 × 1) overlayer of oxygen atoms located at the on-top position above the terminating Zn atom, a structure predicted to be unstable by several density functional theory calculations. The same oxygen overlayer was clearly seen at the interface of ZnO with both elemental and oxidized metal Schottky contact layers. No significant atomic relaxations were observed at surfaces and interfaces processed under typical device fabrication conditions.
Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA. cschlep@aps.anl.gov
Christian M
CM
Schlepütz
Yongsoo
Y
Yang
Naji S
NS
Husseini
Robert
R
Heinhold
Hyung-Suk
HS
Kim
Martin W
MW
Allen
Steven M
SM
Durbin
Roy
R
Clarke
D000465:Algorithms; D010100:Oxygen / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
D015032:Zinc; D010100:Oxygen; D015034:Zinc Oxide