[PDF]    http://dx.doi.org/10.3952/lithjphys.47113

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 47, 81–85 (2007)


MONOLAYER FILM ANALYSIS BY TOTAL INTERNAL REFLECTION ELLIPSOMETRY
V. Vaičikauskas and Z. Balevičius
Institute of Physics, Savanorių 231, LT-02300 Vilnius, Lithuania
E-mail: vikvai@ktl.mii.lt

Received 14 December 2006

The surface plasmon resonance (SPR) method combined with spectral ellipsometry was used to study the chemically formed octadecanthiol (ODT) monolayer on a gold film in Kretchmann configuration. Measurements were made with a commercial spectral ellipsometer GES-5 (SOPRA). The optical constants of an Au film and ODT at 1000 nm wavelength were determined by the best fit procedure from experimental data (Au: n = 0.202, k = 5.970 and ODT: n = 1.4, k = 0). Combination of the SPR method with advantages of phase measurements of ellipsometry demonstrated a substantial increase in sensitivity (more than one order of magnitude) compared with conventional ellipsometry.
Keywords: spectral ellipsometry, surface plasmon resonance, octadecanthiol
PACS: 87.80.y, 73.20.Mf, 78.66.Bz


MONOSLUOKSNIŲ TYRIMAS VISIŠKO VIDAUS ATSPINDŽIO ELIPSOMETRIJA
V. Vaičikauskas, Z. Balevičius
Fizikos institutas, Vilnius, Lietuva

Naudojant spektrinį elipsometrą GES-5, atlikti sistemos prizmė/auksas/oktadekantiolis (ODT) Kretschmann’o konfigūracijoje spektriniai tyrimai. Matuojant amplitudę bei fazę, nustatytos aukso ir ODT sluoksnių optinės konstantos bei storiai. Plazmonų rezonanso elipsometrijos metodo jautrį monosluoksniniams storiams nulemia paviršinių plazmonų lauko pasiskirstymo ypatybės. Paviršinių plazmonų lauko pasiskirstymo maksimumas yra dviejų aplinkų, t. y. metalo ir dielektriko, riboje. Tačiau, esant tam tikroms sąlygoms, kai atspindžio koeficientas artimas nuliui, amplitudinių matavimų signalo ir triukšmo santykis žymiai sumažėja. Kadangi rezonanso sąlygomis atspindėtos bangos fazė taipogi labai keičiasi, tai fazinius matavimus galima panaudoti ir optinėms konstantoms nustatyti. Matavimai parodė, kad, tinkamai parinkus žadinamos bangos ilgį bei metalo sluoksnio storį, galima padidinti metodo jautrį daugiau nei viena eile. Tyrimai su ODT monosluoksniu parodė geras perspektyvas visiško vidinio atspindžio elipsometriją panaudoti tiriant oligomolekules, biomolekules, polimerus bei paviršines chemines reakcijas ir fizikinius procesus metalų paviršiuje.


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