AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP3
The Effects of Temperature and Morphology on the Electron Stimulated Desorption of H@super -@ from Thin Hydrocarbon Films

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: A.D. Bass, University of Sherbrooke, Canada
Authors: A.D. Bass, University of Sherbrooke, Canada
L. Parenteau, University of Sherbrooke, Canada
F. Weik, University of Sherbrooke, Canada
L. Sanche, University of Sherbrooke, Canada
Correspondent: Click to Email
In recent years, low energy electron impact techniques have been used to study thin molecular solids under ultra high vacuum (UHV) and have provided valuable information on the electronic interactions that underlie such phenomena as radiation damage to biological materials, dielectric aging and surface mediated photo-chemistry.@footnote 1@ Measurements of the electron stimulated desorption (ESD) of molecular and atomic anions have in part revealed the importance in radiation damage of such processes as dissociative electron attachment (DEA) and dipolar dissociation (DD). In general, the molecular films used in these studies are formed by vapor deposition under UHV conditions. Until very recently,@footnote 2@,@footnote 3@ little consideration was given as to how film preparation and morphology affected ESD measurements and we address questions of this type in this work. We present measurements of the ESD yield of H@super -@ from pure films of n-hexane, ethyl-benzene and benzene as a function of incident electron energy (0 - 20 eV) at various film temperatures between 20 K and their respective sublimation points. The three molecules were chosen as their films display contrasting degrees of porosity, crystallinity etc., Our measurements reveal the variation in the ESD yield from DEA and DD processes as a function of film temperature (and hence morphology). These changes are correlated to others seen in the low energy electron transmission spectra for films of the same molecules deposited at various temperatures. @FootnoteText@ @footnote 1@See for example L. Sanche, IEEE Trans. Dielec. Elec. Insulat. 4, 507 (1997) @footnote 2@ W.C. Simpson M.T. Sieger, T.M. Orlando, L. Parenteau, K. Nagesha and l. Sanche, J. Chem. Phys. 107 8668 (1997) @footnote 3@K.P. Stevenson, G.A. Kimmel, Z. Dohnalek, R.S. Smith and B.D. Kay, Science 283 1505 (1999).