Maddison, Ronald Charles (1964) Work function changes of clean and contaminated metal films in vacuum and in hydrogen. Doctoral thesis, Keele University.

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Abstract

This investigation is concerned with changes in the work functions of evaporated metal films caused by gas adsorption and variations in temperature. The importance of such changes is underlined by a description of the work function dependent discharge processes, and previous work in the field is reviewed.
The occurrence of cathodic insulating layers in vacua of the order of 10-9 mm.Bs. is demonstrated, and their origin is traced to the glassware of heated manifold components.
The variation of work function with film thickness is investigated and can be explained by the existence of sandwich layer structures of pi and metal and indicates a maximum depth beyond which film discontinuities cease to affect the surface work function.
Temperature variations in work function have been measured in vacua of 10-9 DID.Ha and 10-10 DID.Ha. for several single and superimposed metals and are attributed to temperature dependent adsorption of hydrogen, water vapour and oxygen together with both structural changes within the films and a temperature dependence of work function due to expansion and contraction. The temperature coefficient for the work function of silver is measured as 9.5 x 10-5 ± 11% eV/oC.
The diffusion of hydrogen through heated palladium is investigated as a possible proton source but the only ion emission appears to be that due to thermal desorption from the metal surface on initial heating.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Lisa Bailey
Date Deposited: 19 Mar 2018 14:46
Last Modified: 19 Mar 2018 14:48
URI: http://eprints.keele.ac.uk/id/eprint/4608

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