| AVS 56th International Symposium & Exhibition | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE+TF-TuA |
| Session: | Glancing Angle Deposition II |
| Presenter: | F. Yubero, CSIC, Spain |
| Authors: | A.R. Gonzalez-Elipe, ICMSE (CSIC - U. Seville), Spain F. Yubero, CSIC, Spain J.R. Sanchez-Valencia, ICMSE (CSIC - U. Seville), Spain |
| Correspondent: | Click to Email |
Porosity of thin films is generally estimated in an indirect way by looking to their refraction index. In the present communication we determine directly the porosity of the a series of glancing angle deposited films by measuring the adsorption/desorption of water as a function of the partial pressure of water vapour in contact with the film. The method consists of measuring the changes in the vibration frequency of a quartz crystal monitor (QCM) with its surface covered by the thin films.1 The analysis of the obtained curves permits to estimate the total porosity of the films, its partition between mesopores (pores larger than 2 nm) and micropores (pores smaller than 2 nm) and the pore size distribution function. Results are shown for a series of titanium oxide thin films prepared by evaporation at different glancing angles between 60º and 90º. It is shown that both the total porosity and the partition between meso and micropores change with the evaporation angle. A good correlation exists between these measurements and the optical constants of these films determined by ellipsometry. Analysis of the films by Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) gives some hints to account for the evolution of porosity as a function of the evaporation angle.
1) A. Borrás, J.R. Sánchez-Valencia, J. Garrido-Molinero, A. Barranco, A.R. González-Elipe, Microporous and Mesoporous Materials 118 (2009) 314-324