Overview of variable-angle spectroscopic ellipsometry (VASE): I. Basic theory and typical applications

Woollam, John A.; Johs, B.; Herzinger, C. M.; Hilfiker, James N.; Synowicki, R. A.; Bungay, Corey

doi:10.1117/12.351660

Cited by 171 publications

(144 citation statements)

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“…The fundamental limitations of our technique are thus the experimental error bars and the quality of our least square fitting. This technique has been shown to accurately reproduce optical constants obtained alternately through direct KK analysis of reflectivity, THz time domain spectroscopy, and ellipsometry [38][39][40] . The IR conductivity spectrum σ(ω) can then be found simply from σ(ω) = i…”

Section: Experimental Methodsmentioning

confidence: 99%

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
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We report on infrared (IR) optical experiments on Bi2Te3 and Mn-doped Bi2Te3 epitaxial thin films. In the latter film, dilute Mn doping (4.5%) of the topologically nontrivial semiconductor host results in time-reversal-symmetry-breaking ferromagnetic order below TC =15 K. Our spectroscopic study shows both materials share the Bi2Te3 crystal structure, as well as classification as bulk degenerate semiconductors. Hence the Fermi energy is located in the Bi2Te3 conduction band in both materials, and furthermore, there is no need to invoke topological surface states to describe the conductivity spectra. We also demonstrate that the Drude oscillator strength gives a simple metric with which to distinguish the possibility of topological surface state origins of the low frequency conductance, and conclude that in both the pristine and Mn-doped Bi2Te3 samples the electromagnetic response is indeed dominated by the bulk material properties, rather than those of the surface. An encouraging aspect for taking advantage of the interplay between nontrivial topology and magnetism, however, is that the temperature dependence of the Mn-doped Bi2Te3 film suggests bulk charge carriers do not play a significant role in mediating ferromagnetism. Thus, a truly insulating bulk may still be suitable for the formation of a ferromagnetic ground state in this dilute magnetic topological semiconductor.

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Section: Experimental Methodsmentioning

confidence: 99%

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
View full text Add to dashboard Cite

show abstract

“…There is no fixed MSE value that resolves if a model can be considered correct or not. For thicker films and in-situ measurements, a maximum value of 20 is considered to be reasonable [30].…”

Section: Spectroscopic Ellipsometrymentioning

confidence: 99%

Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

2015

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The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (B5 wt%) and not too low spin speeds (C2000 rpm), the thicknesses of the films agree well with the scaling predicted by the model of Meyerhofer, when methanol or ethanol are used as solvent. The films exhibit uniaxial optical anisotropy with a higher in-plane refractive index, indicating a preferred orientation of the polymer chains in this in-plane direction. The radial shear forces that occur during the spin-coating process do not affect the refractive index and the extent of anisotropy. The anisotropy is due to internal stresses within the thin confined polymer film that are associated with the preferred orientations of the polymer chains. The internal stresses are reduced in the presence of a plasticizer, such as water or an organic solvent, and increase to their original value upon removal of such a plasticizer.

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“…During an indirect fitting procedure 7 the n, k and thickness values in the model are varied until an appropriate fit of the measured  and  spectra is found based on the Mean Square Error (MSE) value. 30 If appropriate MSE values are reached, the actual n, k and thickness values of the model are considered as the ones of the investigated sample.…”

Section: Spectroscopic Ellipsometrymentioning

confidence: 99%

Interactions at the Peptide/Silicon Surfaces: Evidence of Peptide Multilayer Assembly

et al. 2016

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Selective deposition of peptides from liquid solutions to n-and p-doped silicon has been demonstrated. The selectivity is governed by peptide/silicon adhesion differences. A noninvasive, fast characterization of the obtained peptide layers is required to promote their application for interfacing silicon-based devices with biological material. In this study we show that spectroscopic ellipsometry -a method increasingly used for the investigation of biointerfaces -can provide essential information about the amount of adsorbed peptide material and the degree of coverage on silicon surfaces. We observed the formation of peptide multilayers for a strongly binding adhesion peptide on p-doped silicon. Application of the patterned layer ellipsometric evaluation method combined with Sellmeier-dispersion led to physically consistent results, which describe well the optical properties of peptide layers in the visible spectral range.This evaluation allowed the estimation of surface coverage, which is an important indicator of adsorption quality. The ellipsometric findings were well supported by atomic force microscopy results.

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Overview of variable-angle spectroscopic ellipsometry (VASE): I. Basic theory and typical applications

Cited by 171 publications

References 0 publications

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
View full text Add to dashboard Cite

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
View full text Add to dashboard Cite

Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

Interactions at the Peptide/Silicon Surfaces: Evidence of Peptide Multilayer Assembly

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Overview of variable-angle spectroscopic ellipsometry (VASE): I. Basic theory and typical applications

Cited by 171 publications

References 0 publications

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2Chapler1, Post2, Richardella3 et al. 2014Phys. Rev. B243260View full textAdd to dashboardCite

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2Chapler1, Post2, Richardella3 et al. 2014Phys. Rev. B243260View full textAdd to dashboardCite

Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

Interactions at the Peptide/Silicon Surfaces: Evidence of Peptide Multilayer Assembly

Contact Info

Product

Resources

About

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
View full text Add to dashboard Cite

Infrared electrodynamics and ferromagnetism in the topological semiconductorsBi2Te3and Mn-dopedBi2
Chapler
¹
,
Post
²
,
Richardella
³

et al. 2014
Phys. Rev. B
24
3
26
0
View full text Add to dashboard Cite