Search results for "ellipsometry"

Wood fiber orientation assessment based on punctual laser beam excitation: A preliminary study

2016

International audience; The EU imposes standards for the use of wood in structural applications. Local singularities such as knots affect the wood mechanical properties. They can be revealed by looking at the wood fiber orientation. For this reason, many methods were proposed to estimate the orientation of wood fiber using optical means, X-rays, or scattering measurement techniques. In this paper, an approach to assess the wood fiber orientation based on thermal ellipsometry is developed. The wood part is punctually heated with a Nd-YAG Laser and the thermal response is acquired by an infrared camera. The thermal response is elliptical due to the propagation of the heat through and along th…

Thermostability of polymeric langmuir-blodgett films

1991

A user's guide to ellipsometry. By Harland G. Tompkins, Academic Press, New York 1993, 260 pp. hardback, ISBN 0-12-603050-0

1993

Tuning Optical Properties of Al 2 O 3 /ZnO Nanolaminates Synthesized by Atomic Layer Deposition

2014

Nanolaminates are of great interest for their unique properties such as high dielectric constants and advanced mechanical, electrical, and optical properties. Here we report on the tuning of optical and structural properties of Al2O3/ZnO nanolaminates designed by atomic layer deposition (ALD). Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence (PL) spectroscopy. Complex study of monolayer properties was performed by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated. The band gap of ZnO single layers and the excitonic PL peak position were shifted to the UV region …

Surface characterization of functional poly(diacetylene) and poly(butadiene) mono- and multilayers

1982

The surface properties of Langmuir-Blodgett mono- and multilayers of a variety of amphiphilic poly(diacetylene)s and poly(butadiene)s were investigated by contact angle, streaming potentialζ, ellipsometry, and X-ray photoelectron spectroscopic (XPS) measurements. Captive air and octane angles varied between approximately 60° and 105° for hydrophobicx-layers and 31° to 46° for hydrophilic surfaces depending on the particular head group, whereas advancing angles determined via the vertical plate method are considerably higher. Negative streaming potentials were obtained for all surfaces. Positively charged monolayers yielded less negativeζ- potential values (−28 mV) than negatively charged (−…

Formation and Characterization of Self-Assembled Films of Thiol-Derivatized Poly(Dimethylsiloxane) on Gold

1997

Poly(dimethylsiloxane) (PDMS) copolymers containing propanethiol side chain “stickers” for forming self-assembled films on gold surfaces have been studied by various experimental techniques including ellipsometry, contact angle measurements, FT-IR, angle-dependent XPS, and ToF−SIMS. The results show that the thiol-containing side chains do not all chemisorb to the gold surfaces. In addition, the concentration of these sticker units was found to have a dominant effect on the polymer film thickness, the surface wetting properties, and the orientation of the PDMS backbone. Ab initio calculations reveal that the IR-active PDMS Si−O stretching bands can be used as indications of chain orientatio…

Formation of Optical Gradient in Chemical Solution-Derived PbZr[sub 0.52]Ti[sub 0.48]O[sub 3] Thin Films: Spectroscopic Ellipsometry Investigation

2009

Investigation using a variable angle spectroscopic ellipsometer revealed the influence of sample preparation conditions on sol-gel PbZr 0.52 Ti 0.48 O 3 (PZT 52/48) thin-film homogeneity that allows identification and further optimization of thin-film performance. Separate crystallization of the layers determined the optical gradient appearance, irrespective of the chemical solvents used in this work. A more refined analysis showed that a refractive index gradient was apparent in the samples in which lattice parameters strongly changed with thickness. For these films, energy-dispersive X-ray spectroscopy analysis showed significant variation in Pb and Zr. Additionally, complex dielectric fu…

Optical Gradient of the Trapezium-Shaped NaNbO[sub 3] Thin Films Studied by Spectroscopic Ellipsometry

2008

thin films were performed in the photon energy range of 1.24–4.96 eV.Effective values of the complex refractive index and thickness nonuniformity, roughness, and depth profile of the real part of therefractive index were evaluated. An increase of the refractive index with increasing of the sample thickness was observed anddiscussed.© 2008 The Electrochemical Society. DOI: 10.1149/1.2965786 All rights reserved.Manuscript submitted May 27, 2008; revised manuscript received July 7, 2008. Published August 19, 2008.

Porous Aluminium Oxide Coating for the Development of Spectroscopic Ellipsometry Based Biosensor: Evaluation of Human Serum Albumin Adsorption

2020

An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by means of spectroscopic ellipsometry. The determined thickness of the formed pAAO layer obtained from spectroscopic ellipsometry measurements and modelling was 322.75 &plusmn

Aluminum oxide from trimethylaluminum and water by atomic layer deposition:The temperature dependence of residual stress, elastic modulus, hardness a…

2014

Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elastic modulus, hardness and adhesion of ALD aluminum oxide (Al2O3) films grown at 110-300 C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by na…