Method for determination of the parameters of transparent ultrathin films deposited on transparent substrates under conditions of low optical contrast

Abstract

In the present work we suggest an original ellipsometric technique for independently determining strongly correlated refractive index and thickness of transparent ultrathin films. We demonstrate significant accuracy improvement for the single-wavelength null-ellipsometry measurements when using multiple incidence angles for the system "transparent film on a transparent substrate" studied in the thickness range of 1.0-20.0 nm and the low-contrast region for the film-substrate surface. A straightforward relationship is obtained between the refractive index n(1) of the transparent film and the incidence angle φ. It follows from invariability ensured for the amplitude ellipsometric parameter Ψ with respect to the film thickness changes.

Non-cytotoxic, temperature-responsive and antibacterial POEGMA based nanocomposite coatings with silver nanoparticles

“…Thickness and refractive index of graed coatings were examined using ellipsometry. Typical thickness of APTES, measured by ellipsometry was equal to 0.5-1.5 nm (in accord with literature 36,37 ). In turn, the thickness of the ATRP coating used as a substrate for POEGMA188 polymerization was equal to approximately 1 nm.…”

“…The typical thickness of the graed APTES, measured by ellipsometry for the conditions used for glass functionalization, was equal to 0.5 nm. 36,37 The thickness of ATRP lms did not exceed 1 nm.…”

Controlled sub‐10‐nanometer poly(N‐isopropyl‐acrylamide) layers grafted from silicon by atom transfer radical polymerization

“…Table presents the dry thickness for each substrate measured by ellipsometry. Because our procedure leads to ultrathin brush layers, ellipsometry reaches its limits to obtain a reliable value for the layer thickness . To confirm the thickness values determined by ellipsometry, we studied our samples with AFM to derive the polymer layer thickness with a different analytical method.…”

Cholesterol-Based Grafted Polymer Brushes as Alignment Coating with Temperature-Tuned Anchoring for Nematic Liquid Crystals

“…This range of the ϕ angle corresponds to the region of the principal angle of incidence (where Δ ≈ π/2 or 3π/2) and thus ensures maximal sensitivity. To determine the average thickness d and refractive index n for the APTES and oligoperoxide- graft -PChMa coatings, we employ the iterative procedure for fitting of the (Ψ, Δ)-data recorded at optimal experimental conditions, using mono- and two-layer models described in the literature. ,, Raw data for angular dependencies of the ellipsometric parameters for PChMa coating after 12 h of the polymerization are presented in Figure S2.…”