Reflectance difference spectroscopy RDS/RAS combined with spectroscopic ellipsometry for a quantitative analysis of optically anisotropic materials

Rossów, U.; Goldhahn, R.; Fuhrmann, D.; Hangleiter, A.

doi:10.1002/pssb.200541106

Cited by 7 publications

(7 citation statements)

References 53 publications

(52 reference statements)

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“…The RAS determination of anisotropy is also very helpful to verify the ellipsometric data. 39 All measurements were performed under ultrahighvacuum conditions ͑5 ϫ 10 −10 mbar͒ with a rotating analyzer ellipsometer by using a normal-incidence monochromator ͑beamline 3mNIM: 2.5-10 eV͒ and a toroidal grating monochromator ͑beamline TGM-4: 8-35 eV͒ at the Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung ͑BESSY II͒. The polarization vector of the beam was tilted to 20°to the plane of incidence during the ellipsometric measurements.…”

Section: Methodsmentioning

confidence: 99%

Optical spectra of ZnO in the far ultraviolet: First-principles calculations and ellipsometric measurements

et al. 2010

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We present ellipsometry data of the dielectric function of wurtzite ZnO in a wide energy range ͑2.5-32 eV͒. The ordinary and extraordinary components show a strong anisotropy above 10 eV, a feature for which ZnO deviates from the other II-VI wurtzite compounds. With the aid of ab initio calculations, performed within many-body perturbation theory ͑MBPT͒ and within time-dependent density-functional theory ͑TDDFT͒, we analyze the origin of the measured optical structures. TDDFT, with the use of a static long-range exchangecorrelation kernel, proves to be a cheaper computational tool than MBPT to yield a good description of the whole spectrum. Theoretical results for the zinc-blende phase are also presented.

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Section: Methodsmentioning

confidence: 99%

Optical spectra of ZnO in the far ultraviolet: First-principles calculations and ellipsometric measurements

et al. 2010

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“…24,25 Nevertheless, a wide range of metal and semiconductor anisotropic crystalline surfaces have been previously studied by RAS. [24][25][26][27][28][29][30] In contrast, only a few reports on optical anisotropies of metal oxide surfaces exist, mostly focussed on wide band gap materials such as ZnO 31 or superconducting cuprates.…”

Section: -20mentioning

confidence: 99%

Reflectance anisotropy spectroscopy of magnetite (110) surfaces

et al. 2014

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Reflectance anisotropy spectroscopy (RAS) has been used to measure the optical anisotropies of bulk and thin film Fe3O4(110) surfaces. The spectra indicate that small shifts in energy of the optical transitions, associated with anisotropic strain or electric field gradients caused by the (110) surface termination or an native oxide layer, are responsible for the strong signal observed. The RAS response was then measured as a function of temperature. A distinct change in the RAS line shape amplitude was observed in the spectral range from 0.8 to 1.6 eV for temperatures below the Verwey transition of the crystal. Finally thin film magnetite was grown by molecular beam epitaxy on MgO(110) substrates. Changes in the RAS spectra were found for different film thickness, suggesting that RAS can be used to monitor the growth of magnetite (110) films in situ. The thickness dependence of the RAS is discussed in terms of various models for the origin of the RAS signal.

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“…The anisotropy was also investigated by reflectance anisotropy spectroscopy. Fundamentals of the method and experimental details have been published elsewhere [19]. To determine the transition energies of the samples photoluminescence measurements were carried out.…”

Section: Gan (20 5)mentioning

confidence: 99%

“…A simple model, which consists of an anisotropic complex dielectric function with three Lorentz oscillators, was used for the theoretical description. The spectrum was calculated with the formula for RAS signals in [19], the fitted transition energies, and the before determined oscillator strength. is well reproduced in the calculated spectra.…”

Section: Gan (20 5)mentioning

confidence: 99%

Analysis of polarization‐dependent photoreflectance studies for c ‐plane GaN films grown on a ‐plane sapphire

Röppischer¹,

Goldhahn

Buchheim

et al. 2009

Physica Status Solidi (a)

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The optical properties of c ‐plane GaN layers grown by molecular beam epitaxy on a ‐plane sapphire substrate are investigated. Polarization‐dependent photoreflectance spectroscopy was applied with the electric field vector of the probe beam being either parallel or perpendicular to the [10$ \bar 1 $0] direction of the GaN films. A pronounced in‐plane optical anisotropy under normal incidence of light is observed which is attributed to anisotropic in‐plane strain. It originates from the difference of the thermal expansion coefficients of the substrate parallel and perpendicular to its c‐axis. Temperature‐dependent studies and a comparison to photoluminescence and reflectance anisotropy studies indicate that the strain (anisotropy) increases with decreasing sample temperature. The dependence of transition energies and oscillator strengths of GaN as a function of strain values is calculated by k·p perturbation theory for comparison. The results emphasize the experimental data. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Reflectance difference spectroscopy RDS/RAS combined with spectroscopic ellipsometry for a quantitative analysis of optically anisotropic materials

Cited by 7 publications

References 53 publications

Optical spectra of ZnO in the far ultraviolet: First-principles calculations and ellipsometric measurements

Optical spectra of ZnO in the far ultraviolet: First-principles calculations and ellipsometric measurements

Reflectance anisotropy spectroscopy of magnetite (110) surfaces

Analysis of polarization‐dependent photoreflectance studies for c ‐plane GaN films grown on a ‐plane sapphire

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