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A Novel Method for True Work Function Determination of Metal Surfaces by Combined Kelvin Probe and Photoelectric Effect Measurements

Published online by Cambridge University Press:  10 February 2011

Bert Lägel ,
Iain D. Baikie ,
Konrad Dirscherl  and
Uwe Petermann
Bert Lägel
Affiliation:
Department of Applied Physics, The Robert Gordon University, Aberdeen, UK
Iain D. Baikie
Affiliation:
Department of Applied Physics, The Robert Gordon University, Aberdeen, UK
Konrad Dirscherl
Affiliation:
Department of Applied Physics, The Robert Gordon University, Aberdeen, UK
Uwe Petermann
Affiliation:
Department of Applied Physics, The Robert Gordon University, Aberdeen, UK
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Abstract

We have developed a novel method for in-situ measurements of the true work function (ø) of metal surfaces by combined ultra-high vacuum compatible Kelvin Probe and photoelectric effect measurements. The work function is an extremely sensitive parameter of surface condition and can be used to study oxidation and thin film growth on metal surfaces. For example, the increase in ø due to oxidation of polycrystalline rhenium is 1.9eV.

The Kelvin Probe measures local work function differences between a conducting sample and a reference tip in a non-contact, truly non-invasive way over a wide temperature range. However, it is an inherently relative technique and does not provide an absolute work function if the work function of the tip (øtip) is unknown.

We present a novel approach to measure øtip with the Kelvin Probe via the photoelectric effect, using a Gd foil as the photoelectron source, hereby combining the advantages of both methods to provide the absolute work function of the sample surface. We demonstrate the application of the technique by in-situ work function measurements during oxidation of polycrystalline rhenium. The extended Kelvin Probe method therefore has potential applications as a characterisation tool for thin film epitaxy and work function engineering of surfaces.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 619: Symposium L – Recent Developments in Oxide & Metal Epitaxy – Theory… , 2000 , 73
Copyright
Copyright © Materials Research Society 2000

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References

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