AN INVESTIGATION OF INELASTIC ELECTRON TUNNELLING SPECTROSCOPY

This thesis describes the work carried out in the initiation of a research programme to investigate Inelastic Electron Tunnelling Spectroscopy (lETS). A description of the technique of lETS is given. As the main aim of this work was to produce a working facility for lETS, details of the construction of an lET spectrometer are given. This is followed by a description of the preparation of tunnel junctions, including oxide formation and doping methods. The importance of strict cleaning procedures is stressed, particularly when using liquid phase doping. A new sample holder which is directly immersible into standard liquid helium dewars is described. The experimental techniques are evaluated by comparing spectra obtained in this work with those published by other workers. The effect of electrode resistance on lET spectral lines is discussed. It is shown that care must be taken to ensure that non-superconducting electrodes are sufficiently thick to minimise their resistance. The effect of having electrodes with too high a resistance is investigated experimentally; it is found that peak shifts and broadenings may occur as a result of these effects. It is also shown that the shifts and broadenings are more pronounced when wide electrodes are used as opposed to narrow electrodes. The adsorption of the three isomers of benzenedicarboxylic acid and phthalic anhydride on to aluminium oxide is investigated. It has been possible to identify the spectra of the different adsorbed isomers, and to suggest the surface adsorbate species formed Orientations of the three isomers on the oxide surface have been suggested. A calculation of the Coulomb potential between the carboxylate oxygen ions of the benzenedicarboxylic acid anions and a model oxide lattice is carried out. This has enabled a variety of different possible adsorption sites to be investigated regarding their suitability for absorption. Finally, a suggestion is made to explain the origin of a previously unassigned peak which occurs in many lET spectra, namely the peak near 2900 cm -1.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

1983

Author dc:creator

• TUNNICLIFFE, DAVID LESLIE

Licence

• https://dora.dmu.ac.uk/bitstreams/e03bc0d7-fcfb-4f5a-800f-67c5edf4b8cc/download