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Electronic And Structural Properties Of Interfaces Created By Potassium Deposition ON TiO2 (110) Surfaces

Published online by Cambridge University Press:  25 February 2011

R. J. Lad  and
L. S. Dake
R. J. Lad
Affiliation:
Laboratory for Surface Science & Technology, University of Maine, Orono, ME 04469.
L. S. Dake
Affiliation:
Laboratory for Surface Science & Technology, University of Maine, Orono, ME 04469.
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Abstract

Potassium was deposited onto stoichiometric TiO2 (110) surfaces and the chemical bonding and structure were studied with UPS, XPS, LEED, and RHEED. Potassium interacts strongly with the oxygen anions of the TiO2 and reduces the valency of Ti cations at the interface. At submonolayer potassium coverages, a large charge transfer to the substrate causes a sharp drop in work function, a population of electronic states within the bulk TiO2 band gap, and surface band bending. After large potassium doses at 300 K, multilayers of K2O are formed by diffusion of oxygen anions from the substrate, creating a substoichiometric TiO2−x interface composition. No metallic potassium is present even after large doses. The K2O layers remain stable after annealing as high as 900 K, and LEED indicates that they are disordered. RHEED characterization is limited by the roughness of the stoichiometric TiO2 (110) surface.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 238: Symposium Cb – Structure and Properties of Interfaces in Materials , 1991 , 823
Copyright
Copyright © Materials Research Society 1992

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