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Search for "valence" in Full Text gives 336 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.

Graphical Abstract
  • electrons are excited from the trapped states existing near the valence band (EV). In addition, the a-IGZO TFTs inevitably suffer electrical and optical stresses during practical operation conditions, especially for the negative bias and illumination stress (NBIS) tests [11][12][13][14][15][16], which leads
  • increasing photon energy. Note that the photoleakage current increases dramatically in the photon energy range of >2.7 eV for the TFT with the thicker TIGZO. These results indicate that the electrons are excited from the trapped states existing near the valence band (EV) to the conduction band (EC) even
  • oxygen-related defects, such as oxygen vacancies (VO), may be the origin of high-density electron traps near the EV in a-IGZO TFTs, which occupy the region near the valence band maximum with an energy width of ≈1.5 eV [26][27]. Figure 3a–d shows the variation in the transfer characteristics of a-IGZO
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Published 26 Sep 2018

Non-agglomerated silicon–organic nanoparticles and their nanocomplexes with oligonucleotides: synthesis and properties

  • Asya S. Levina,
  • Marina N. Repkova,
  • Nadezhda V. Shikina,
  • Zinfer R. Ismagilov,
  • Svetlana A. Yashnik,
  • Dmitrii V. Semenov,
  • Yulia I. Savinovskaya,
  • Natalia A. Mazurkova,
  • Inna A. Pyshnaya and
  • Valentina F. Zarytova

Beilstein J. Nanotechnol. 2018, 9, 2516–2525, doi:10.3762/bjnano.9.234

Graphical Abstract
  • . The IR spectrum of Si–NH2 shows the local environment of the silicon atom (Figure 2a). The presence of the absorption bands that correspond to valence and deformation vibrations of the CH2, NH2, NH3+, Si–CH2, Si–OH, (Si–O)n, C–N groups [19] confirm the proposed structure of the Si–NH2 molecule. The
  • splitting of the absorption band at 1085 cm−1, which corresponds to asymmetric valence vibrations of the Si–O bond, into two bands at 1100 cm−1 and 1000 cm−1 is typical for polymer structures with Si–O–Si fragments and indicates the presence of at least dimers in the Si–NH2 nanoparticles. The bands at 3058
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Published 21 Sep 2018

Surface energy of nanoparticles – influence of particle size and structure

  • Dieter Vollath,
  • Franz Dieter Fischer and
  • David Holec

Beilstein J. Nanotechnol. 2018, 9, 2265–2276, doi:10.3762/bjnano.9.211

Graphical Abstract
  • atomic diameter (≈0.288 nm). This correction is material dependent since its origin is the extent of the electronic cloud [54], which depends on the number of valence electrons, density of material (i.e., spatial density of atoms), etc. One also expects that this correction slightly increases with
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Published 23 Aug 2018

Intrinsic ultrasmall nanoscale silicon turns n-/p-type with SiO2/Si3N4-coating

  • Dirk König,
  • Daniel Hiller,
  • Noël Wilck,
  • Birger Berghoff,
  • Merlin Müller,
  • Sangeeta Thakur,
  • Giovanni Di Santo,
  • Luca Petaccia,
  • Joachim Mayer,
  • Sean Smith and
  • Joachim Knoch

Beilstein J. Nanotechnol. 2018, 9, 2255–2264, doi:10.3762/bjnano.9.210

Graphical Abstract
  • behaviour together with the ΔE by the quantum-chemical properties of Si, N and O. Both anions, N and O, dominate electronic bonds to Si by delocalizing a substantial partition of Si valence electrons to form strong polar bonds [13], giving rise to ICT from usn-Si into the respective dielectric (SiO2, Si3N4
  • ) [14]. A high ionicity of bond (IOB) and strong negative electron affinity (X) of O result in a strong localization of Si-NC valence electrons. This localization corresponds to increased binding energies – the ICT shifts all MOs away from Evac. N is the only anionic element with a positive X [29] which
  • is key for ΔE together with the smaller IOB of N to Si. Unlike O, the valence electrons delocalized from Si-NCs are not strongly localized at N due to its positive X and lower IOB to Si. Such delocalized MOs correspond to states with substantially lowered binding energy, yielding to a shift of MOs
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Published 23 Aug 2018

Lead-free hybrid perovskites for photovoltaics

  • Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

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Published 21 Aug 2018

Spin-coated planar Sb2S3 hybrid solar cells approaching 5% efficiency

  • Pascal Kaienburg,
  • Benjamin Klingebiel and
  • Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

Graphical Abstract
  • measurements [67]. The HOMO of KP115 is thus better aligned with the valence band of Sb2S3 which could be beneficial for the Voc and FF. Indeed, for the Sb-TU process both values are significantly larger for the better-matching KP115. However, this is not the case for the Sb-BDC process where the Sb2S3/KP115
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Published 08 Aug 2018

A scanning probe microscopy study of nanostructured TiO2/poly(3-hexylthiophene) hybrid heterojunctions for photovoltaic applications

  • Laurie Letertre,
  • Roland Roche,
  • Olivier Douhéret,
  • Hailu G. Kassa,
  • Denis Mariolle,
  • Nicolas Chevalier,
  • Łukasz Borowik,
  • Philippe Dumas,
  • Benjamin Grévin,
  • Roberto Lazzaroni and
  • Philippe Leclère

Beilstein J. Nanotechnol. 2018, 9, 2087–2096, doi:10.3762/bjnano.9.197

Graphical Abstract
  • illumination. Evac, Ec, Ev, Ef and Φ stand for vacuum level, conduction band, valence band, Fermi level and workfunction, respectively. HOMO and LUMO mean highest occupied molecular orbital and lowest unoccupied molecular orbital, respectively. (a) 400 × 400 nm2 AFM height image obtained in air on a TiO2/P3HT
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Published 01 Aug 2018

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

  • Mattia Scardamaglia and
  • Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

Graphical Abstract
  • , phosphorus has five valence electrons, but its atomic radius is bigger. Therefore, its incorporation in the carbon lattice causes a protrusion out of the graphitic plane [47]. Other functional groups containing oxygen [50], hydrogen [51][52] or fluorine [53][54][55], also contribute to the modification of
  • valence band (VB) spectra with high energy resolution [58]. They correlated the change in the DOS to the different types of nitrogen functionalities incorporated in the carbon matrix, using X-ray photoemission spectroscopy and in situ annealing. Specifically, it was shown that through annealing at
  • treatments were reported to promote the conversion of pyridinic N into graphitic N and the fine-tuning of the density of states at the Fermi level, which increases proportionally to the content of graphitic N in the carbon lattice. The five valence electrons of the N atoms are distributed differently. Thus
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Published 18 Jul 2018

Synthesis of a MnO2/Fe3O4/diatomite nanocomposite as an efficient heterogeneous Fenton-like catalyst for methylene blue degradation

  • Zishun Li,
  • Xuekun Tang,
  • Kun Liu,
  • Jing Huang,
  • Yueyang Xu,
  • Qian Peng and
  • Minlin Ao

Beilstein J. Nanotechnol. 2018, 9, 1940–1950, doi:10.3762/bjnano.9.185

Graphical Abstract
  • compositions and the valence states of MnO2/Fe3O4/diatomite, and the spectra are shown in Figure 6. The Si 2p, O 1s, Fe 2p and Mn 2p peaks detected in the survey spectrum (Figure 6a) indicate the existence of Si, Fe, Mn, and O. The high-resolution scans for Fe 2p, Mn 2p and O 1s are also represented in Figure
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Published 06 Jul 2018

Numerical analysis of single-point spectroscopy curves used in photo-carrier dynamics measurements by Kelvin probe force microscopy under frequency-modulated excitation

  • Pablo A. Fernández Garrillo,
  • Benjamin Grévin and
  • Łukasz Borowik

Beilstein J. Nanotechnol. 2018, 9, 1834–1843, doi:10.3762/bjnano.9.175

Graphical Abstract
  • . Experimental Photo-carrier generation is a process that takes place in semiconductor materials when electron–hole pairs (positive and negative polarons in the case of organic photovoltaics) are created by exciting an electron from the valence band to the conduction band (π-electrons from the highest occupied
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Published 20 Jun 2018

Improving the catalytic activity for hydrogen evolution of monolayered SnSe2(1−x)S2x by mechanical strain

  • Sha Dong and
  • Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

Graphical Abstract
  • ] and agrees well with previous results [36]. SnS2 and SnSe2 monolayers are indirect-bandgap semiconductors, as highlighted in their band structures shown in Figure 1e and Figure 1i, respectively. The valence-band maximum (VBM) is located at the M-point, whereas the conduction-band minimum (CBM) is
  • increases upon application of tensile strain because the valence band and conduction band move upward and downward in energy, respectively. Previous reports showed that H adsorption depends on the density of states near the Fermi energy level [57][58], with the adsorption being enhanced as the d-band centre
  • and SnSe0.5S1.5 monolayers with strains of −5%, −3%, 2%, 6% and 10%. As seen from Figure 5, there are fewer valence states near the Fermi energy when compressive strain is applied, and the number of electronic states increases with increasing tensile strain. A higher density of electronic states near
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Published 18 Jun 2018

Uniform cobalt nanoparticles embedded in hexagonal mesoporous nanoplates as a magnetically separable, recyclable adsorbent

  • Can Zhao,
  • Yuexiao Song,
  • Tianyu Xiang,
  • Wenxiu Qu,
  • Shuo Lou,
  • Xiaohong Yin and
  • Feng Xin

Beilstein J. Nanotechnol. 2018, 9, 1770–1781, doi:10.3762/bjnano.9.168

Graphical Abstract
  • [38]. XPS was used to investigate the surface composition of the sample NPLs-2.5-800 and the valence state of the elements. The elements Co, Al, C, O, and N can be clearly observed in the full survey XPS spectrum (Figure 6B). The two characteristic peaks located at 780.8 eV and 796.5 eV in the Co 2p
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Published 13 Jun 2018

Sulfur-, nitrogen- and platinum-doped titania thin films with high catalytic efficiency under visible-light illumination

  • Boštjan Žener,
  • Lev Matoh,
  • Giorgio Carraro,
  • Bojan Miljević and
  • Romana Cerc Korošec

Beilstein J. Nanotechnol. 2018, 9, 1629–1640, doi:10.3762/bjnano.9.155

Graphical Abstract
  • of the band gap by introducing a new energy level close to the valence band. Nitrogen doping can also create impurity energy levels above the valence band, thus effectively also narrowing the band gap [35][36]. Illumination with visible light can then excite electrons from impurity energy levels into
  • illumination (k1 for S3_N0.5 is 0.30 h−1). The band gap width for this sample was shown to be narrowed (3.07 eV). Researchers attribute this to a synergetic effect between N 2p and S 3p orbitals, resulting in a hybridization of the two orbitals generated close to the valence band [31][49]. Furthermore, with
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Published 04 Jun 2018

Interaction-tailored organization of large-area colloidal assemblies

  • Silvia Rizzato,
  • Elisabetta Primiceri,
  • Anna Grazia Monteduro,
  • Adriano Colombelli,
  • Angelo Leo,
  • Maria Grazia Manera,
  • Roberto Rella and
  • Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

Graphical Abstract
  • Avogadro’s number, kB is Boltzmann’s constant, T is the absolute temperature and is the ionic strength whereby the electrolyte solution contains ion of type i with valence zi and molar concentration ci. Therefore, the strength of electrostatic interaction between the colloidal particles on the surface can
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Published 29 May 2018

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

  • Daniel Hiller,
  • Julian López-Vidrier,
  • Keita Nomoto,
  • Michael Wahl,
  • Wolfgang Bock,
  • Tomáš Chlouba,
  • František Trojánek,
  • Sebastian Gutsch,
  • Margit Zacharias,
  • Dirk König,
  • Petr Malý and
  • Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

Graphical Abstract
  • Si, typical dopant ionization energies are in the range of ≈50 meV. If the size of the Si crystal approaches the exciton Bohr-radius, strong quantum confinement sets in and the valence- and conduction band ground state energies shift to lower and higher energies, respectively. As a consequence, the
  • situation is less critical since the conduction band offset of Si NCs and SiO2 is only about half that of the valence band offset [56]. Figure 7a shows I–t-transients of the injection-blocked MOS-capacitors (the inset depicts a schematic cross-section) measured at 0.2 MV/cm, i.e., at the onset of the J-peak
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Published 18 May 2018

Cr(VI) remediation from aqueous environment through modified-TiO2-mediated photocatalytic reduction

  • Rashmi Acharya,
  • Brundabana Naik and
  • Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

Graphical Abstract
  • surface of the semiconductor. When photons with energy greater than the band gap energy of the semiconductor photocatalyst (SP) are absorbed, photogenerated electrons are excited to conduction band (CB) leaving behind holes at the valence band (VB) as per Equation 1: These photogenerated species
  • cases, hole scavengers are used to facilitate the electron–hole separation process. However, application of TiO2 in photocatalysis is largely restricted mainly due to the following reasons. (i) The wide band gap of 3.2 eV causes excitation of electrons from the valence band under irradiation of UV light
  • , or B narrows the band gap either by creating a mid-band gap or shifting the valence band to upper positions, resulting in a redshift. Even modification of titania with semiconductor oxides or sulfides improves the light absorption. It was evident from UV–vis DRS spectra that light absorption is
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Published 16 May 2018

Robust midgap states in band-inverted junctions under electric and magnetic fields

  • Álvaro Díaz-Fernández,
  • Natalia del Valle and
  • Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

Graphical Abstract
  • states are accurately described by means of a two-band model using the effective k·p approximation [18][19]. The equation governing the conduction- and valence-band envelope functions reduces to a Dirac-like equation after neglecting far-band corrections. In view of this analogy, exact solutions can be
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Published 14 May 2018

Predicting the strain-mediated topological phase transition in 3D cubic ThTaN3

  • Chunmei Zhang and
  • Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1399–1404, doi:10.3762/bjnano.9.132

Graphical Abstract
  • ThTaN3 at a lower compressive strain (5%) as shown in Figure 4. The conduction band (CB) state mainly consisted of px, py and pz orbitals of the N atom, while the valence band (VB) state is comprised of the hybridization dxy, dxz, dyz orbitals of the Ta atom. When the SOC effect was incorporated, a p–d
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Published 11 May 2018

New 2D graphene hybrid composites as an effective base element of optical nanodevices

  • Olga E. Glukhova,
  • Igor S. Nefedov,
  • Alexander S. Shalin and
  • Мichael М. Slepchenkov

Beilstein J. Nanotechnol. 2018, 9, 1321–1327, doi:10.3762/bjnano.9.125

Graphical Abstract
  • operator vector; me and e are the free-electron mass and electron charge; En(k) and Em(k) and are the sub-band energies of, respectively, valence band and conductivity band. The spin degeneracy is already taken into account in the above equations by the factor 2, η is a phenomenological parameter
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Published 30 Apr 2018

Ag2WO4 nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

  • Shijie Li,
  • Shiwei Hu,
  • Wei Jiang,
  • Yanping Liu,
  • Yu Liu,
  • Yingtang Zhou,
  • Liuye Mo and
  • Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 1308–1316, doi:10.3762/bjnano.9.123

Graphical Abstract
  • the CB of AgI (and more holes left behind in the valence band (VB)) could readily attack the pollutant molecules, resulting in the remarkable photocatalytic performance of AgI/Ag2WO4. Conclusion In summary, a novel heterojunction photocatalyst comprised of AgI nanoparticle-decorated Ag2WO4 nanorods
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Published 27 Apr 2018

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

  • Tarek A. Ameen,
  • Hesameddin Ilatikhameneh,
  • Archana Tankasala,
  • Yuling Hsueh,
  • James Charles,
  • Jim Fonseca,
  • Michael Povolotskyi,
  • Jun Oh Kim,
  • Sanjay Krishna,
  • Monica S. Allen,
  • Jeffery W. Allen,
  • Rajib Rahman and
  • Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

Graphical Abstract
  • states in valence and conduction bands, Fi = 1, while Ff depends on the energy level and doping. Normally, quantum dots are occupied by a number of electrons equal to the average number of dopants per dot [34]. This approach is reasonable for quantum dots that are far from heavily doped regions. However
  • the wavefunctions of the electrons and holes are localized due to these disordered band edges, as the spatial overlap between the states determines the optical absorption spectrum. Hence, one can look at the conduction and valence band edges along arbitrary lines passing through the quantum dot. This
  • confinement increases the minimum allowed energy of electron Eelec and hole Ehole with respect to the band edges. Let Ebox = Eelec + Ehole, then the transition energy E is Due to the sign of the deformation potential and strain, the valence band edge inside the quantum dot is of a heavy hole, from Equation 4
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Published 04 Apr 2018

Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg1−xCdxTe

  • Alexandra V. Galeeva,
  • Alexey I. Artamkin,
  • Alexey S. Kazakov,
  • Sergey N. Danilov,
  • Sergey A. Dvoretskiy,
  • Nikolay N. Mikhailov,
  • Ludmila I. Ryabova and
  • Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 1035–1039, doi:10.3762/bjnano.9.96

Graphical Abstract
  • concentrations correspond to the Fermi level position not lower than at 3 meV, 5 meV, and 7 meV above the conduction band edge for the samples with x = 0.13, 0.15, 0.17, respectively. The energy distance between the conduction band and the light-hole valence subband used in the Kane model calculations was
  • band structure) in the samples with x < 0.16. Variable position edges of the conduction (Ec) band, the heavy hole valence (Ev) subband, and the light hole subband in the heterojunction are schematically shown by black solid lines. The Fermi level is shown by the dash-dot line. The topological layer
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Published 29 Mar 2018

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

  • Sahar Pakdel,
  • Mahdi Pourfath and
  • J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

Graphical Abstract
  • feature a band inversion. In a gedanken experiment, one can imagine tuning the SOC at will. As the SOC is increased from zero towards its nominal value, it pushes up the valence band while bringing down the conduction band of the imaginary SOC-free material. In this process, the gap closes and reopens
  • , however, are usually restricted to the description of valence electrons, implicitly by assuming a minimal basis set of spd orbitals. The SOC is included by adding the matrix elements of the operator where λ is taken as an atomic parameter [8]. Although the simplicity of TB modeling is appealing, this
  • for the interstitial or valence electrons, while approaching the core electrons differently. Since localized orbitals are convenient for a number of reasons, for instance for quantum transport calculations [15][16], a Kohn–Sham Hamiltonian obtained from plane-wave DFT codes may be transformed into a
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Published 28 Mar 2018

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

  • Abdulrahman Altin,
  • Maciej Krzywiecki,
  • Adnan Sarfraz,
  • Cigdem Toparli,
  • Claudius Laska,
  • Philipp Kerger,
  • Aleksandar Zeradjanin,
  • Karl J. J. Mayrhofer,
  • Michael Rohwerder and
  • Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

Graphical Abstract
  • valence band (VB) edge region. The ZnO VB region contains contributions from overlapping Zn 4s/4p, O 2p and C 2p levels [29][30]. Because of (i) the significantly bigger excitation cross-section for ZnO compared to β-CD, and (ii) the expected atomic contributions to the VB region, this region can be
  • ) Zn 2p3/2, (d) Zn 3d - valence band (VB) energy region, with ZnO VB onset and ZnO VB maximum as functions of the TOA (inset). (e) Binding-energy variations for recorded spectral regions with TOA; (f) UPS HOMO onset of β-CD recorded with He II excitation. The Auger parameter α is shown as inset in (c
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Published 20 Mar 2018

Effect of annealing treatments on CeO2 grown on TiN and Si substrates by atomic layer deposition

  • Silvia Vangelista,
  • Rossella Piagge,
  • Satu Ek and
  • Alessio Lamperti

Beilstein J. Nanotechnol. 2018, 9, 890–899, doi:10.3762/bjnano.9.83

Graphical Abstract
  • permittivity (κ) of 23–24 [5]. In all the cases, the valence of the Ce ions is fundamental, since it determines some of the material specific ability, such as the oxygen storage. More generally, the structure of cerium oxide is essential in defining its specific capabilities [6]. At the thermodynamic
  • phase or sub-stoichiometric CeO2 (CeO2−δ) can easily form. The cerium ion valence and the ceria structure can be influenced by the substrate onto which the film is grown and by thermal treatment after its deposition [7]. Also, the structural and/or the chemical composition of the substrate can influence
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Published 15 Mar 2018
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