A reverse Monte Carlo method for deriving optical constants of solids from reflection electron energy-loss spectroscopy spectra

Da, Bo; Sun, Yang; Mao, Shifeng; Zhang, Z. M.; Jiang, Hua; Yoshikawa, Hideki; Tanuma, Shigeo; Ding, Zejun

doi:10.1063/1.4809544

Cited by 48 publications

(28 citation statements)

References 73 publications

(73 reference statements)

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“…Therefore, in this work, we aim at a revision of the optical properties of silicon and germanium. In recent years, a well-established highprecision technique, based on a combination of the reflection electron energy loss spectroscopy (REELS) measurements and the so-called reversed Monte Carlo (RMC) method [11], was developed to obtain optical constants of elements in a wide range of electron energy loss. The key to obtaining good results by RMC is the high-precision theoretical analysis of the high energy resolution experimental data.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of silicon and germanium determined by high-precision analysis of reflection electron energy loss spectroscopy spectra

et al. 2019

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We present a detailed analysis and comparison of four models describing the extension of the electron-energy loss function from the optical limit of q→0 into the (q,ω) plane to obtain the bulk and surface terms of differential inverse inelastic mean free paths. We found that the best model that describes accurately and times efficiently the calculation of the energy loss function of free-electron-like materials is the combination of the Penn algorithm [Phys. Rev. B 35, 482 (1987)] with the Ritchie-Howie method [Philos. Mag. 36, 463 (1977)]. Applying this model in our reverse Monte Carlo method, we determined, with high-precision, electron-energy loss functions of silicon and germanium based on the theoretical analysis of the high-energy resolution reflected electron energy loss spectroscopy (REELS) spectra, measured at 3, 4, and 5 keV incident electron energies. The refractive index n, the extinction coefficient k, and the complex dielectric function (ε = ε 1 + iε 2 ) were calculated from the obtained energy loss function in a wide energy loss range of 0-200 eV. The accuracy of the obtained results is justified with various sum rules. We found that the calculated optical data of Si and Ge fulfill the sum rules with an average accuracy of 0.11% or even better. Therefore, the use of these optical data in materials science and surface analysis is highly recommended for further applications.

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Section: Introductionmentioning

confidence: 99%

Optical properties of silicon and germanium determined by high-precision analysis of reflection electron energy loss spectroscopy spectra

et al. 2019

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“…Although absolute values of optical constants were obtained successfully by the RMC method for SiO2, 15 it still needs further improvements for elemental solids with complex electronic structures, such as transition metals. This is because the previous simplification, i.e.…”

Section: -21mentioning

confidence: 99%

“…A significant improvement has been recently achieved based on a new numerical modelling, 15 namely the so called reverse Monte Carlo (RMC) method which integrates Monte Carlo (MC) simulation of REELS spectrum and Marokv chain Monte Carlo (MCMC) technique for updating of ELF during the calculation.…”

Section: -21mentioning

confidence: 99%

“…On the other hand, the electron energy loss spectroscopy [3][4][5] can provide alternative way for deriving information of dielectric response of solid to external electric field carried by electrons, which is, in principal rather different technique compared with optical methods. In recent years a technique based on the reflection electron energy loss spectroscopy (REELS) has been developed [6][7][8][9][10][11][12][13][14][15][16] to obtain optical constants in a rather wide range of energy loss of electrons (i.e. photon energy).…”

Section: Eli-alps Eli-hu Non-profit Ltd Dugonics Té R 13 H-6720 Smentioning

confidence: 99%

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Absolute determination of optical constants by reflection electron energy loss spectroscopy

Tóth

et al. 2017

Phys. Rev. B

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We present an absolute extraction method of optical constants of metal from the measured reflection electron energy loss (REELS) spectra by using the recently developed reverse Monte Carlo (RMC) technique. The method is based on a direct physical modeling of electron elastic and electron inelastic scattering near the surface region where the surface excitation becomes important to fully describe the spectrum loss feature intensity in relative to the elastic peak intensity. An optimization procedure of oscillator parameters appeared in the energy loss function (ELF) for describing electron inelastic scattering due to the bulk-and surfaceexcitations was performed with the simulated annealing method by a successive comparison between the measured and Monte Carlo simulated REELS spectra. The ELF and corresponding optical constants of Fe were obtained from the REELS spectra measured at incident energies of 1000, 2000 and 3000 eV. The validity of the present optical data has been verified with the f-and ps-sum rules showing the accuracy and applicability of the present approach. Our data are also compared with previous optical data from other sources.There is a continuous interest and effort on the determination of optical constants of solids due to their importance in both fundamental researches and applications. Optical methods based on reflectance and absorption spectroscopy with ellipsometry were extensively employed up to now and the measured data for metals and semiconductors were compiled to form a database of optical constants.1,2 However, many materials still lack the data in the intermediate photon energy range around 20~50 eV. Furthermore, the available data usually consist of different energy regions measured by different groups and means and, a)

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“…In this work we present an improved reverse Monte Carlo (RMC) method [1] so as to precisely describe complicated electron scattering process in REELS and thus to extract optical constants of a nano-structured nickel film. This method consists of an iterative process of global searching optical data modeling parameters by comparing Monte Carlo simulated REELS spectra with experimental measurement.…”

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Extended reverse Monte Carlo method for extracting optical constants of thin Ni film from reflection electron energy-loss spectroscopy

Mao

et al. 2015

J. Phys.: Conf. Ser.

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Synopsis An extended reverse Monte Carlo (RMC) method for obtaining optical constants of ultrathin films and solids is presented. Our results show that this method works very well in extracting some exquisite information from experimentally measured reflection electron energy loss spectroscopy (REELS) spectra. The energy loss function (ELF) of 100 nm nickel film in a relatively larger energy loss range of 0-200 eV has been obtained, which agrees well with other computational data. Employing this ELF, individual contributions to REELS intensity due to surface and bulk plasmon excitations are quantitatively separated for further study.

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A reverse Monte Carlo method for deriving optical constants of solids from reflection electron energy-loss spectroscopy spectra

Cited by 48 publications

References 73 publications

Optical properties of silicon and germanium determined by high-precision analysis of reflection electron energy loss spectroscopy spectra

Optical properties of silicon and germanium determined by high-precision analysis of reflection electron energy loss spectroscopy spectra

Absolute determination of optical constants by reflection electron energy loss spectroscopy

Extended reverse Monte Carlo method for extracting optical constants of thin Ni film from reflection electron energy-loss spectroscopy

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