Hostname: page-component-7479d7b7d-q6k6v Total loading time: 0 Render date: 2024-07-11T21:44:23.307Z Has data issue: false hasContentIssue false
  • English
  • Français

Work Function Study of Polycrystalline Metals using a UHV Scanning Kelvin Probe

Published online by Cambridge University Press:  14 March 2011

U. Petermann ,
I.D. Baikie ,
B. Lägel  and
K.M. Dirscherl
U. Petermann
Affiliation:
Department of Applied Physics, Robert Gordon University, Aberdeen, UK
I.D. Baikie
Affiliation:
Department of Applied Physics, Robert Gordon University, Aberdeen, UK
B. Lägel
Affiliation:
Department of Applied Physics, Robert Gordon University, Aberdeen, UK
K.M. Dirscherl
Affiliation:
Department of Applied Physics, Robert Gordon University, Aberdeen, UK
Get access

Abstract

We have undertaken a study of high work function (φ) surfaces as part of an ongoing project searching for efficient target materials for use in Hyperthermal Surface Ionisation (HSI), a new mass spectroscopy ionisation technique. HSI relies on high work function surfaces for the production of positive ions. Polycrystalline metals as Re, W, Mo and Pt are particularly interesting materials in this respect as oxidation substantially increases their φ. We present and discuss the following experimental evidence: a) the magnitude and sign of φ changes in terms of adsorbate induced dipoles, b) the effect of molecular hydrogen exposure on the clean surface, and c) the effect of subsequent oxygen exposure.

Using a novel UHV Scanning Kelvin Probe we have followed the oxidation kinetics of polycrystalline metals at different temperatures and examined the effects of oxidation, flash annealing and sputter-anneal cleaning cycles via high-resolution φ topographies. Our results indicate in particular Re as a suitable HSI target material exhibiting a φ increase of 1050 meV at 300 K increasing to 2050 meV at 900 K. Sputter-cleaned surfaces exhibit a dramatic change in the second oxidation phase.

We have also examined φ changes associated with N2O and CO2 on Tungsten and Molybdenum. We observe that atomic oxygen gives similar results to O2 but has a much lower initial sticking coefficient. We report that CO2 actually lowers the φ for substrate temperatures under 650 K, the peak work function changes occurs at 850 K and is approximately 1/3 the height of the O2 or O peak.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 615: Symposium G – Polycrystalline Metal & Magnetic Thin Films - 2000 , 2000 , G6.6.1
Copyright
Copyright © Materials Research Society 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Danon, A. and Amirav, A., Rev. Sci. Instrum., 58, 1724 (1987).10.1063/1.1139374Google Scholar
2. Amirav, A.. Org. Mass Spectrom. 26, 1 (1991).10.1002/oms.1210260102Google Scholar
3. Kelvin, Lord, Philos. Mag. 46, 82 (1898).10.1080/14786449808621172Google Scholar
4. Zisman, W.A., Rev. Sci. Instrum., 3, 367 (1932).10.1063/1.1748947Google Scholar
5. Baikie, I.D., Venderbosch, E., Meyer, J.A. and Estrup, P.J, Rev. Sci. Instrum., 62, 725 (1991).10.1063/1.1142075Google Scholar
6. Baikie, I. D., Mackenzie, S., Estrup, P.J. Z. and Meyer, J.A., Rev. Sci. Instrum., 62, 1326 (1991).10.1063/1.1142494Google Scholar
7. Ritty, B., Wachtel, F., Manquenouille, R., Ott, F. and Donnet, J.B., J. Phys. E. 15, 310 (1982).10.1088/0022-3735/15/3/017Google Scholar
8. Baikie, I.D., Mat.Res. Soc. Proc, 204, 363 (1991).10.1557/PROC-204-363Google Scholar
9. Baikie, I.D., Petermann, U. and Lägel, B., Surf. Sci. 433–435, 249 (1999).10.1016/S0039-6028(99)00026-6Google Scholar
10. Meyer, J.A., Baikie, I.D., Lopinski, G.P., Prybyla, J.A. and Estrup, P.J., J. Vac. Sci. Technol., A8, 2468 (1990).10.1116/1.576717Google Scholar
11. Kopatzhi, E., Keck, H-G, Baikie, I.D., Meyer, J.A. and Behm, R.J., Surf. Sci. 345, L11 (1996).10.1016/0039-6028(95)01008-4Google Scholar
12. Meyer, J.A., Baikie, I.D., Kopatzki, E. and Behm, R.J., Surf. Sci. 365, L647 (1996).10.1016/0039-6028(96)00852-7Google Scholar
13. Baikie, I.D., Petermann, U. and Lägel, B., Surf. Sci. 433–435, 770 (1999).10.1016/S0039-6028(99)00140-5Google Scholar
14. Baikie, I.D. and Bruggink, G.H., Mat. Res. Soc. Proc., 309, 35 (1993).10.1557/PROC-309-35Google Scholar
15. Lägel, B., Baikie, I.D. and Petermann, U., Mat. Res. Soc. Proc., 510, 619 (1998).10.1557/PROC-510-619Google Scholar
16. Lägel, B., Baikie, I.D. and Petermann, U., Surf. Sci. 433–435, 622 (1999).10.1016/S0039-6028(99)00025-4Google Scholar
17. Baikie, I.D. and Bruggink, G.H., Mat. Res. Soc. Proc., 306, 311 (1993).Google Scholar
18. Petermann, U., Baikie, I.D. and Lägel, B., Thin Solid Films 343–344, 492 (1999).10.1016/S0040-6090(98)01657-5Google Scholar
19. Höfer, U., Morgen, P., Wurth, W., Phy. Rev. B40, 1130 (1989).10.1103/PhysRevB.40.1130Google Scholar
20. Baikie, I.D., Ph. D. Thesis, Univ of Twente (1988), ISBN 90-9002444-1.Google Scholar
21. Baikie, I.D., Werf, K.O. van der, Broeze, J. and Silfhout, A van, Rev. Sci. Instrum., 60, 930 (1989).10.1063/1.1140346Google Scholar
22. Baikie, I.D. and Estrup, P.J., Rev. Sci. Instrum, 69, 3902 (1998).10.1063/1.1149197Google Scholar
23. Fusy, J., Bigeard, B., Cassuto, A., Surf. Sci. 46, 177 (1974).10.1016/0039-6028(74)90247-7Google Scholar
24. Zehner, D.M., Farnsworth, H.E., Surf. Sci. 30, 335 (1972).10.1016/0039-6028(72)90006-4Google Scholar
25. Gorodetskii, D.A. and Knysh, A.N., Sov. Phys.-Solid State, 13, 2219 (1972)Google Scholar
26. Pantel, R. and Bujor, M., Surf. Sci. 83, 228 (1979).10.1016/0039-6028(79)90489-8Google Scholar