Optical constants determination of complex organic films by spectroscopic ellipsometry from the UV to the mid-IR Ella Sciamma-O’Brien1, Pierre-Richard Dahoo1,3, Edith Hadamcik1, Nathalie Carrasco1, Eric Quirico2, Cyril Szopa1, Bernard Schmitt2, Guy Cernogora1 1
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Université Versailles St-Quentin, UMPC Univ. Paris 06, CNRS, LATMOS, Réduit de Verrières, 91371 Verrières le Buisson Cedex, France
Université Joseph Fourier, CNRS/INSU, Laboratoire de Planétologie de Grenoble UMR 5109, Bâtiment D de Physique, BP 53, 38041 Grenoble Cedex 9, France
3
Département de Physique, Mécanique, Sciences pour L’ingénieur et Environnement, Université Versailles St-Quentin; 45 Avenue des Etats-Unis, 78035, Versailles Cedex, France,
[email protected]
We have used a low pressure RF (13.56 MHz) Capacitively Coupled Plasma (RF CCP) discharge called PAMPRE [1], to produce thin films of complex organic compounds from chemistry induced by the dissociation of N2 and CH4 by electron impact. A complex organic chemistry leads to the production of complex molecules and the subsequent production of solid material. A part of this material is made of spherical solid particles formed and growing in suspension in the gas phase [2] and another part constitutes thin films deposited onto solid substrates. In the study presented here, a N2-CH4 gas mixture containing 5% of CH4 was used, and thin films were deposited simultaneously onto three different 1 inch diameter substrates: a 3 mm thick CaF2 substrate, an aluminum mirror covered with a layer of SiO2 about 160 nm thick and a gold mirror covered with a layer of SiO2 about 200 nm thick. Plasma duration was tuned in order to obtain thin films up to a thickness of 2 μm. Using ellipsometers from J.A. Woollam Co. to cover the spectral range from near UV to mid infrared, that is an M-2000 and an IR-VASE, spectroscopic ellipsometry parameters were measured from 0.4 μm to 1 μm and from 1.7 μm to 30.0 μm respectively. Substrates were optically characterized prior to deposition of complex organic films using Woollam’s VASE analysis software. The films were analyzed to determine the real and imaginary parts, n and k, of the complex refractive index of the deposited films. These data are essential for a correct modeling of atmospheres of planets where similar complex organic substances are present. We present here the first results of this study. References [1] Szopa, C., Cernogora, G., Boufendi, L., Correia, J.-J. and Coll, P. (2006) Planet. Space Sci., 54, 394-404. [2] E. Hadamcik, J.B Renard,.G.Alcouffe, G.Cernogora, A.C.Levasseur-Regourd,C. Szopa Planet. Space Sci. 57, 1631-1641 (2009). Presenting Author:
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