Universal dispersion model for characterization of optical thin films over wide spectral range: Application to magnesium fluoride

Franta, Daniel; Nečas, David; Giglia, Angelo; Franta, Pavel; Ohlı́dal, Ivan

doi:10.1016/j.apsusc.2016.09.149

Cited by 7 publications

(7 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…were used in addition to the ellipsometric data (I s , I c , I n ) f measured from the side with the GdF 3 film (front side) and the data (I s , I c , I n ) b measured from the opposite side (back side). Although these data are not independent, the inclusion of difference ellipsometry in the data processing helps to reduce the influence of the substrate and systematic errors [2,5]. In the UV and VIS spectral range, where the silicon substrate is not transparent, the ellipsometry was also measured from the back side in order to determine the thickness of the native oxide layer.…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…According to our experience, similar to difference ellipsometry, the relative reflectance helps to reduce the correlations between the sought parameters by compensating for systematic errors in measurement [2,5].…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…This dispersion model satisfies three fundamental conditions: time reversal symmetry, Kramers-Kronig consistency and conformity with the sum rules. The UDM is a suitable dispersion model for a very precise description of the response function of optical materials in a wide spectral range [2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical Characterization of Gadolinium Fluoride Films Using Universal Dispersion Model

et al. 2023

Self Cite

View full text Add to dashboard Cite

The optical characterization of gadolinium fluoride (GdF3) films is performed in a wide spectral range using heterogeneous data-processing methods (the ellipsometric and spectrophotometric measurements for five samples with thicknesses ranging from 20 to 600 nm are processed simultaneously). The main result of the characterization is the optical constants of GdF3 in the range from far infrared to vacuum ultraviolet, both in the form of a table and in the form of dispersion parameters of the universal dispersion model (UDM). Such reliable data in such a broad spectral range have not been published so far. The GdF3 films exhibit several defects related to the porous polycrystalline structure, namely, surface roughness and a refractive index profile, which complicate the optical characterization. The main complication arises from the volatile adsorbed components, which can partially fill the pores. The presented optical method is based on the application of the UDM for the description of the optical response of GdF3 films with partially filled pores. Using this dispersion model, it is possible to effectively separate the optical response of the host material from the response of the adsorbed components. Several recently published structural and dispersion models are used for optical characterization for the first time. For example, a model of inhomogeneous rough films based on Rayleigh–Rice theory or asymmetric peak approximation with a Voigt profile for the phonon spectra of polycrystalline materials.

show abstract

Section: Experimental Arrangementmentioning

confidence: 99%

Section: Experimental Arrangementmentioning

confidence: 99%

See 1 more Smart Citation

Optical Characterization of Gadolinium Fluoride Films Using Universal Dispersion Model

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nevertheless, it should be noted that in principle it is possible to separate the interband transitions into the valence to conduction band transitions and into the high energy excitations of valence electrons since each of them has different dependence on temperature. This separation is convenient if the experimental data extending to the synchrotron spectral region are processed [31][32][33].…”

Section: N T E R B a N D T R A N S I T I O N S I N D I S O R D E Rementioning

confidence: 99%

Temperature dependent dispersion models applicable in solid state physics

Franta

Vohánka

Čermák

et al. 2019

Journal of Electrical Engineering

Self Cite

View full text Add to dashboard Cite

Dispersion models are necessary for precise determination of the dielectric response of materials used in optical and microelectronics industry. Although the study of the dielectric response is often limited only to the dependence of the optical constants on frequency, it is also important to consider its dependence on other quantities characterizing the state of the system. One of the most important quantities determining the state of the condensed matter in equilibrium is temperature. Introducing temperature dependence into dispersion models is quite challenging. A physically correct model of dielectric response must respect three fundamental and one supplementary conditions imposed on the dielectric function. The three fundamental conditions are the time-reversal symmetry, Kramers-Kronig consistency and sum rule. These three fundamental conditions are valid for any material in any state. For systems in equilibrium there is also a supplementary dissipative condition. In this contribution it will be shown how these conditions can be applied in the construction of temperature dependent dispersion models. Practical results will be demonstrated on the temperature dependent dispersion model of crystalline silicon.

show abstract

“…The dielectric functions of materials (Si, SiO 2 , doped Si), necessary for these calculations, were acquired from past work , (represented as ε lit in Figure ). However, the published optical data on MgF 2 , and Al 2 O 3 ,, films vary widely due to different deposition conditions and sample preparation. Therefore, we directly measured the optical constants for MgF 2 and Al 2 O 3 for free-space wavelengths 1.7–33 μm with a spectroscopic ellipsometer (see Supporting Information).…”

mentioning

confidence: 99%

Probing the Limits to Near-Field Heat Transfer Enhancements in Phonon-Polaritonic Materials

et al. 2023

View full text Add to dashboard Cite

Near-field radiative heat transfer (NFRHT) arises between objects separated by nanoscale gaps and leads to dramatic enhancements in heat transfer rates compared to the far-field. Recent experiments have provided first insights into these enhancements, especially using silicon dioxide (SiO2) surfaces, which support surface phonon polaritons (SPhP). Yet, theoretical analysis suggests that SPhPs in SiO2 occur at frequencies far higher than optimal. Here, we first show theoretically that SPhP-mediated NFRHT, at room temperature, can be 5-fold larger than that of SiO2, for materials that support SPhPs closer to an optimal frequency of 67 meV. Next, we experimentally demonstrate that MgF2 and Al2O3 closely approach this limit. Specifically, we demonstrate that near-field thermal conductance between MgF2 plates separated by 50 nm approaches within nearly 50% of the global SPhP bound. These findings lay the foundation for exploring the limits to radiative heat transfer rates at the nanoscale.

show abstract

Universal dispersion model for characterization of optical thin films over wide spectral range: Application to magnesium fluoride

Cited by 7 publications

References 19 publications

Optical Characterization of Gadolinium Fluoride Films Using Universal Dispersion Model

Optical Characterization of Gadolinium Fluoride Films Using Universal Dispersion Model

Temperature dependent dispersion models applicable in solid state physics

Probing the Limits to Near-Field Heat Transfer Enhancements in Phonon-Polaritonic Materials

Contact Info

Product

Resources

About