Reflection electron energy loss spectroscopy of nanometric oxide layers and of their interfaces with a substrate

Paumier, F.; Fouquet, V.; Guittet, M.-J.; Gautier-Soyer, M.; French, Roger H.; Tan, Guolong; Chiang, Yet Ming; Tang, Ming; Ramos, A. V.; Chung, Sung‐Yoon

doi:10.1016/j.msea.2006.01.005

Cited by 15 publications

(11 citation statements)

References 39 publications

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“…In order to extract the dielectric function, it is first necessary to perform a decomposition into bulk and surface contributions of the experimental VEEL spectrum measured in inner beam geometry. The underlying assumption is that the single scattering cross section can be expressed as a linear combination of the bulk Im[−1/ε(ω)] and surface Im[−1/(1 + ε(ω))] energy loss functions: [ 51,52 ]

\begin{matrix} Im ([], - \frac{1}{ε}) = \frac{ε_{2}}{ε_{1}^{2} + ε_{2}^{2}} \end{matrix}

\begin{matrix} Im ([], - \frac{1}{ε + 1}) = \frac{ε_{2}}{{(ε_{1} + 1)}^{2} + ε_{2}^{2}} \end{matrix}

where ε 1 and ε 2 are the real and imaginary parts of the total dielectric function ε. Here, we note that Equations (1) and (2) are typical for bulk materials, and can be modified in case of nanomaterials due to quantum confinement effects, as explained in ref.…”

Section: Resultsmentioning

confidence: 99%

The Advantage of Nanowire Configuration in Band Structure Determination

Dimitrievska

Hage

Steinvall

et al. 2021

Adv Funct Materials

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Earth-abundant and environmentally friendly semiconductors offer a promising path toward low-cost mass production of solar cells. A critical aspect in exploring new semiconducting materials and demonstrating their enhanced functionality consists in disentangling them from the artifacts of defects. Nanowires are diameter-tailored filamentary structures that tend to be defectfree and thus ideal model systems for a given material. Here, an additional advantage is demostrated, which is the determination of the band structure, by performing high energy and spatial resolution electron energy-loss spectroscopy in aloof and inner beam geometry in a scanning transmission electron microscope. The experimental results are complemented by spectroscopic ellipsometry and are excellently correlated with first principles calculations. This study opens the path for characterizing the band structure of new compounds in a non-destructive and prompt manner, strengthening the route of new materials discovery.

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\begin{matrix} Im ([], - \frac{1}{ε}) = \frac{ε_{2}}{ε_{1}^{2} + ε_{2}^{2}} \end{matrix}

\begin{matrix} Im ([], - \frac{1}{ε + 1}) = \frac{ε_{2}}{{(ε_{1} + 1)}^{2} + ε_{2}^{2}} \end{matrix}

Section: Resultsmentioning

confidence: 99%

The Advantage of Nanowire Configuration in Band Structure Determination

Dimitrievska

Hage

Steinvall

et al. 2021

Adv Funct Materials

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“…22,37,38 Furthermore, the E g electron affinity (E A ) and ionization potential (I P ) of the Zr-hybrid dielectric were extracted from the reflective electron energy loss spectroscopy (REELS) with low-loss spectra and ultra-violet photoelectron spectroscopy (UPS) (Figure S7a,b in Supporting Information). 39,40 The Zrhybrid dielectrics had an electron affinity (E A ) of 2.7−3.1 eV and an I P of 8.0−8.3 eV (Figure 4b). The Zr-hybrid dielectrics at different Zr concentrations had an energy band gap in the range of 5.2−5.4 eV and exhibited a sufficient valence-band offset of around 3.0 eV from the pentacene semiconductor.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Ultrathin ZrO_x-Organic Hybrid Dielectric (EOT 3.2 nm) via Initiated Chemical Vapor Deposition for High-Performance Flexible Electronics

Kim

Pak

Choi

et al. 2019

ACS Appl. Mater. Interfaces

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A one-step synthesis method is introduced and used to form an ultrathin, homogeneous organic–inorganic hybrid dielectric film with a high dielectric constant (high-k), based on initiated chemical vapor deposition. The hybrid dielectric is synthesized from tetrakis-dimethyl-amino-zirconium and 2-hydroxyethyl methacrylate, which are a high-k inorganic material and a soft organic material, respectively. A detailed material analysis on the synthesized ZrO x -organic hybrid (Zr-hybrid) is performed. The Zr-hybrid dielectric has a high dielectric constant of nine, leading to a film equivalent oxide thickness (EOT) as low as 3.2 nm, which is the lowest EOT obtained from a flexible dielectric layer to date. The leakage current density (J) is no larger than 6 × 10–7 A/cm2 at 2 MV/cm, and the breakdown field (E break) was ∼3.3 MV/cm. The J of the Zr-hybrid dielectric remains almost constant even under the 2.5% strain condition, while that of the ZrO2 dielectric breaks down electrically at a tensile strain of less than 1.0%. The Zr-hybrid dielectric shows an energy band gap in the range of 5.2–5.4 eV and exhibits a sufficient valence band offset of around 3.0 eV with a pentacene organic semiconductor. The gate stack of the Zr-hybrid dielectric/pentacene semiconductor shows decent metal–oxide–semiconductor field-effect transistor performance even under a tensile strain of 1.67%, indicating that the Zr-hybrid is a promising gate dielectric for advanced flexible electronic applications.

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“…While vacuum‐medium excitations have been extensively analysed, interface excitations occurring at the medium‐medium (“MM”) interface are up to now less considered. Since the pioneer work of Raether, a non‐negligible number of theoretical and experimental works about MM interface excitations has obviously been published, but there does not exist a general parameter – as the SEP for surface excitation – that characterizes MM interface excitation. It is precisely the goal of this work to propose an expression for the so‐called interface excitation parameter (IEP).…”

Section: Introductionmentioning

confidence: 99%

Interface excitation parameter from dielectric response theory

Vanbever

Pauly

Dubus

2015

Surface & Interface Analysis

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We define the interface excitation parameter (IEP) as the change in excitation probability, caused by the presence of a medium‐medium interface crossed by an electron, in comparison with an electron for which only bulk excitations are considered. This definition is established by analogy with the definition of the surface excitation parameter for which one of the two media of the interface is the vacuum and which has already been extensively studied. To calculate the IEP (as well as the energy‐differential IEP or DIEP), we generalize the model developed by Tung, Chen, Kwei and Chou [C. J. Tung, Y. F. Chen, C. M. Kwei and T. L. Chou, Phys. Rev. B 49 (1994) 16684] from dielectric response theory for surface excitation parameter determination. We perform these calculations for angles between 0o and 60o, for electron energies between 200 and 3000eV and for various combinations of materials, chosen for their academic (as Al/In) or practical interest (as SiO2/Si for instance). We show that for materials with “similar” dielectric properties (metal/metal), the IEP is completely negligible. On the contrary when the materials of the interface are characterized by a large energy band gap difference, as metal/insulator or semiconductor/insulator, the IEP can reach a value of about 0.26 for the smallest electron energies considered here. Moreover, we show that for the SiO2/Si interface, the energy‐differential IEP obtained from our model is in good agreement with previous experimental data. Copyright © 2015 John Wiley & Sons, Ltd.

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Reflection electron energy loss spectroscopy of nanometric oxide layers and of their interfaces with a substrate

Cited by 15 publications

References 39 publications

The Advantage of Nanowire Configuration in Band Structure Determination

The Advantage of Nanowire Configuration in Band Structure Determination

Ultrathin ZrO_x-Organic Hybrid Dielectric (EOT 3.2 nm) via Initiated Chemical Vapor Deposition for High-Performance Flexible Electronics

Interface excitation parameter from dielectric response theory

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Reflection electron energy loss spectroscopy of nanometric oxide layers and of their interfaces with a substrate

Cited by 15 publications

References 39 publications

The Advantage of Nanowire Configuration in Band Structure Determination

The Advantage of Nanowire Configuration in Band Structure Determination

Ultrathin ZrOx-Organic Hybrid Dielectric (EOT 3.2 nm) via Initiated Chemical Vapor Deposition for High-Performance Flexible Electronics

Interface excitation parameter from dielectric response theory

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Product

Resources

About

Ultrathin ZrO_x-Organic Hybrid Dielectric (EOT 3.2 nm) via Initiated Chemical Vapor Deposition for High-Performance Flexible Electronics