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Costantini JM, Ribis J. Analysis of Plasmon Loss Peaks of Oxides and Semiconductors with the Energy Loss Function. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7610. [PMID: 38138750 PMCID: PMC10744408 DOI: 10.3390/ma16247610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/23/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023]
Abstract
This paper highlights the use and applications of the energy loss function (ELF) for materials analysis by using electron energy loss spectroscopy (EELS). The basic Drude-Lindhart theory of the ELF is briefly presented along with reference to reflection electron energy loss (REELS) data for several dielectric materials such as insulating high-k binary oxides and semiconductors. Those data and their use are critically discussed. A comparison is made to the available ab initio calculations of the ELF for these materials. Experimental, high-resolution TEM-EELS data on Si, SiC, and CeO2 obtained using a high-resolution, double-Cs-corrected transmission electron microscope are confronted to calculated spectra on the basis of the ELF theory. Values of plasmon energies of these three dielectric materials are quantitatively analyzed on the basis of the simple Drude's free electron theory. The effects of heavy ion irradiation on the TEM-EELS spectra of Si and SiC are addressed. In particular, the downward shifts of plasmon peaks induced by radiation damage and the subsequent amorphization of Si and SiC are discussed. TEM-EELS data of CeO2 are also analyzed with respect to the ELF data and with comparison to isostructural ZrO2 and PuO2 by using the same background and with reference to ab initio calculations.
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Affiliation(s)
- Jean-Marc Costantini
- Service de Recherche en Matériaux et Procédés Avancés, Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France;
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2
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Baskakov SA, Baskakova YV. Granulated Graphene Oxide/Titanium Dioxide Composite Aerogel as a High-Performance Photocatalyst. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143920020022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Gnacadja E, Pauly N, Tougaard S. Universal inelastic electron scattering cross‐section including extrinsic and intrinsic excitations in XPS. SURF INTERFACE ANAL 2020. [DOI: 10.1002/sia.6749] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Eustache Gnacadja
- Service de Métrologie NucléaireUniversité libre de Bruxelles (CP 165/84) Brussels Belgium
| | - Nicolas Pauly
- Service de Métrologie NucléaireUniversité libre de Bruxelles (CP 165/84) Brussels Belgium
| | - Sven Tougaard
- Department of Physics, Chemistry and PharmacyUniversity of Southern Denmark Odense Denmark
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4
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Suryani S, Heryanto, Tahir D. Stopping powers and inelastic mean free path from quantitative analysis of experimental REELS spectra for electrons in Ti, Fe, Ni, and Pd. SURF INTERFACE ANAL 2019. [DOI: 10.1002/sia.6713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sri Suryani
- Physics DepartmentHasanuddin University Makassar Indonesia
| | - Heryanto
- Physics DepartmentHasanuddin University Makassar Indonesia
| | - Dahlang Tahir
- Physics DepartmentHasanuddin University Makassar Indonesia
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5
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Appel O, Cohen S, Beeri O, Shamir N, Gelbstein Y, Zalkind S. Surface Oxidation of TiNiSn (Half-Heusler) Alloy by Oxygen and Water Vapor. MATERIALS 2018; 11:ma11112296. [PMID: 30445807 PMCID: PMC6267011 DOI: 10.3390/ma11112296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/08/2018] [Accepted: 11/10/2018] [Indexed: 11/16/2022]
Abstract
TiNiSn-based half-Heusler semiconducting compounds have the highest potential as n-type thermoelectric materials for the use at elevated temperatures. In order to use these compounds in a thermoelectric module, it is crucial to examine their behaviour at a working temperature (approximately 1000 K) under oxygen and a humid atmosphere. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were utilized to study the surface composition and oxidation of the TiNiSn alloy at elevated temperatures. It was found that during heating in vacuum, Sn segregates to the surface. Exposing the alloy to oxygen at room temperature will cause surface oxidation of Ti to TiO2 and Ti2O3 and some minor oxidation of Sn. Oxidation at 1000 K induces Ti segregation to the surface, creating a titanium oxide layer composed of mainly TiO2 as well as Ti2O3 and TiO. Water vapor was found to be a weaker oxidative gas medium compared to oxygen.
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Affiliation(s)
- Oshrat Appel
- Department of Materials Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel.
- Nuclear Research Centre-Negev, POB 9001, Beer-Sheva 84190, Israel.
| | - Shai Cohen
- Nuclear Research Centre-Negev, POB 9001, Beer-Sheva 84190, Israel.
| | - Ofer Beeri
- Nuclear Research Centre-Negev, POB 9001, Beer-Sheva 84190, Israel.
| | - Noah Shamir
- Department of Materials Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel.
| | - Yaniv Gelbstein
- Department of Materials Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel.
| | - Shimon Zalkind
- Nuclear Research Centre-Negev, POB 9001, Beer-Sheva 84190, Israel.
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Cushing SK, Zürch M, Kraus PM, Carneiro LM, Lee A, Chang HT, Kaplan CJ, Leone SR. Hot phonon and carrier relaxation in Si(100) determined by transient extreme ultraviolet spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2018; 5:054302. [PMID: 30246050 PMCID: PMC6133686 DOI: 10.1063/1.5038015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/22/2018] [Indexed: 05/16/2023]
Abstract
The thermalization of hot carriers and phonons gives direct insight into the scattering processes that mediate electrical and thermal transport. Obtaining the scattering rates for both hot carriers and phonons currently requires multiple measurements with incommensurate timescales. Here, transient extreme-ultraviolet (XUV) spectroscopy on the silicon 2p core level at 100 eV is used to measure hot carrier and phonon thermalization in Si(100) from tens of femtoseconds to 200 ps, following photoexcitation of the indirect transition to the Δ valley at 800 nm. The ground state XUV spectrum is first theoretically predicted using a combination of a single plasmon pole model and the Bethe-Salpeter equation with density functional theory. The excited state spectrum is predicted by incorporating the electronic effects of photo-induced state-filling, broadening, and band-gap renormalization into the ground state XUV spectrum. A time-dependent lattice deformation and expansion is also required to describe the excited state spectrum. The kinetics of these structural components match the kinetics of phonons excited from the electron-phonon and phonon-phonon scattering processes following photoexcitation. Separating the contributions of electronic and structural effects on the transient XUV spectra allows the carrier population, the population of phonons involved in inter- and intra-valley electron-phonon scattering, and the population of phonons involved in phonon-phonon scattering to be quantified as a function of delay time.
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Affiliation(s)
| | - Michael Zürch
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Peter M Kraus
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | | | - Angela Lee
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Hung-Tzu Chang
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Christopher J Kaplan
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Klyushin AY, Jones TE, Lunkenbein T, Kube P, Li X, Hävecker M, Knop-Gericke A, Schlögl R. Strong Metal Support Interaction as a Key Factor of Au Activation in CO Oxidation. ChemCatChem 2018. [DOI: 10.1002/cctc.201800972] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Alexander Yu. Klyushin
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
- Division of Energy Material; Helmholtz-Zentrum Berlin für Materialien und Energie GmbH; Albert-Einstein-Str. 15 Berlin 12489 Germany
| | - Travis E. Jones
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
| | - Thomas Lunkenbein
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
| | - Pierre Kube
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
| | - Xuan Li
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
| | - Michael Hävecker
- Department of Heterogeneous Reactions; Max-Planck-Institute for Chemical Energy Conversion; Stiftstrasse 34-36 Mülheim an der Ruhr 45470 Germany
| | - Axel Knop-Gericke
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
| | - Robert Schlögl
- Department of Inorganic Chemistry; Fritz Haber Institute of the Max Planck Society; Faradayweg 4-6 Berlin 14195 Germany
- Division of Energy Material; Helmholtz-Zentrum Berlin für Materialien und Energie GmbH; Albert-Einstein-Str. 15 Berlin 12489 Germany
- Department of Heterogeneous Reactions; Max-Planck-Institute for Chemical Energy Conversion; Stiftstrasse 34-36 Mülheim an der Ruhr 45470 Germany
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Cushing SK, Chen CJ, Dong CL, Kong XT, Govorov AO, Liu RS, Wu N. Tunable Nonthermal Distribution of Hot Electrons in a Semiconductor Injected from a Plasmonic Gold Nanostructure. ACS NANO 2018; 12:7117-7126. [PMID: 29945441 DOI: 10.1021/acsnano.8b02939] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
For semiconductors photosensitized with organic dyes or quantum dots, transferred electrons are usually considered thermalized at the conduction band edge. This study suggests that the electrons injected from a plasmonic metal into a thin semiconductor shell can be nonthermal with energy up to the plasmon frequency. In other words, the electrons injected into the semiconductor are still hot carriers. Photomodulated X-ray absorption measurements of the Ti L2,3 edge are compared before and after excitation of the plasmon in Au@TiO2 core-shell nanoparticles. Comparison with theoretical predictions of the X-ray absorption, which include the heating and state-filling effects from injected hot carriers, suggests that the electrons transferred from the plasmon remain nonthermal in the ∼10 nm TiO2 shell, due in part to a slow trapping in defect states. By repeating the measurements for spherical, rod-like, and star-like metal nanoparticles, the magnitude of the nonthermal distribution, peak energy, and number of injected hot electrons are confirmed to be tuned by the plasmon frequency and the sharp corners of the plasmonic nanostructure. The results suggest that plasmonic photosensitizers can not only extend the sunlight absorption spectral range of semiconductor-based devices but could also result in increased open circuit voltages and elevated thermodynamic driving forces for solar fuel generation in photoelectrochemical cells.
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Affiliation(s)
| | - Chih-Jung Chen
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Chung Li Dong
- Department of Physics , Tamkang University , Tamsui 25137 , Taiwan
| | - Xiang-Tian Kong
- Institute of Fundamental and Frontier Sciences and State Key Laboratory of Electronic Thin Films and Integrated Devices , University of Electronic Science and Technology of China , Chengdu 610054 , China
- Department of Physics and Astronomy , Ohio University , Athens , Ohio 45701 , United States
| | - Alexander O Govorov
- Department of Physics and Astronomy , Ohio University , Athens , Ohio 45701 , United States
| | - Ru-Shi Liu
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
- Department of Mechanical Engineering and Graduate Institute of Manufacturing Technology , National Taipei University of Technology , Taipei 10617 , Taiwan
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Paul B, Björk EM, Kumar A, Lu J, Eklund P. Nanoporous Ca 3Co 4O 9 Thin Films for Transferable Thermoelectrics. ACS APPLIED ENERGY MATERIALS 2018; 1:2261-2268. [PMID: 29905306 PMCID: PMC5995460 DOI: 10.1021/acsaem.8b00333] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/27/2018] [Indexed: 05/28/2023]
Abstract
The development of high-performance and transferable thin-film thermoelectric materials is important for low-power applications, e.g., to power wearable electronics, and for on-chip cooling. Nanoporous films offer an opportunity to improve thermoelectric performance by selectively scattering phonons without affecting electronic transport. Here, we report the growth of nanoporous Ca3Co4O9 thin films by a sequential sputtering-annealing method. Ca3Co4O9 is promising for its high Seebeck coefficient and good electrical conductivity and important for its nontoxicity, low cost, and abundance of its constituent raw materials. To grow nanoporous films, multilayered CaO/CoO films were deposited on sapphire and mica substrates by rf-magnetron reactive sputtering from elemental Ca and Co targets, followed by annealing at 700 °C to form the final phase of Ca3Co4O9. This phase transformation is accompanied by a volume contraction causing formation of nanopores in the film. The thermoelectric propoperties of the nanoporous Ca3Co4O9 films can be altered by controlling the porosity. The lowest electrical resistivity is ∼7 mΩ cm, yielding a power factor of 2.32 × 10-4 Wm-1K-2 near room temperature. Furthermore, the films are transferable from the primary mica substrates to other arbitrary polymer platforms by simple dry transfer, which opens an opportunity of low-temperature use these materials.
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Affiliation(s)
- Biplab Paul
- Thin
Film Physics Division, Department of Physics, Chemistry, and
Biology (IFM), and Nanostructured Materials, Department of Physics, Chemistry, and Biology
(IFM),Linköping University, SE-581 83 Linköping, Sweden
| | - Emma M. Björk
- Thin
Film Physics Division, Department of Physics, Chemistry, and
Biology (IFM), and Nanostructured Materials, Department of Physics, Chemistry, and Biology
(IFM),Linköping University, SE-581 83 Linköping, Sweden
| | - Aparabal Kumar
- Materials
Science Centre, Indian Institute of Technology, Kharagpur 721302, India
| | - Jun Lu
- Thin
Film Physics Division, Department of Physics, Chemistry, and
Biology (IFM), and Nanostructured Materials, Department of Physics, Chemistry, and Biology
(IFM),Linköping University, SE-581 83 Linköping, Sweden
| | - Per Eklund
- Thin
Film Physics Division, Department of Physics, Chemistry, and
Biology (IFM), and Nanostructured Materials, Department of Physics, Chemistry, and Biology
(IFM),Linköping University, SE-581 83 Linköping, Sweden
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10
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Wiesing M, Grundmeier G. Lifshitz analysis of dispersion forces based on quantitative reflection electron energy loss spectroscopy. J Colloid Interface Sci 2018; 514:625-633. [PMID: 29306193 DOI: 10.1016/j.jcis.2017.12.069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/22/2017] [Accepted: 12/26/2017] [Indexed: 10/18/2022]
Abstract
HYPOTHESIS The energy loss experienced by an electron while moving through a solid is determined by the optical properties of the surrounding. Hence, quantitative Reflection Electron Energy Loss Spectroscopy (REELS) should allow the determination of optical data required for the calculation of Hamaker coefficients using Lifshitz theory. This approach might improve the accuracy of calculated Hamaker coefficients and should also enable to harness the unique capabilities of REELS to analyse nanostructured surfaces and thin-films with great spatial resolution and surface sensitivity. EXPERIMENTS REELS spectra of a survey of insulating polymers and of metal-like Ti0.23Al0.32N0.44 (TiAlN) were measured, the complex dielectric functions determined and the corresponding Hamaker coefficients across vacuum and water calculated. The sensitivity of the quantification procedure towards typical systematic errors was investigated. For polystyrene the results were comparatively analysed using vacuum ultraviolet spectroscopy (VUV). FINDINGS The accuracy especially of the non-retarded vacuum Hamaker constants of the polymers was increased when compared to VUV reflectance spectroscopy due to the higher spectral range of REELS. Furthermore, a new correction procedure for the intricate case of unresolved inelastic losses in the REELS spectrum, such as encountered in the case of TiAlN, could be developed using spectroscopic ellipsometry as a complementary mean.
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Affiliation(s)
- M Wiesing
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany.
| | - G Grundmeier
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
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11
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Enhancing PEM water electrolysis efficiency by reducing the extent of Ti gas diffusion layer passivation. J APPL ELECTROCHEM 2018. [DOI: 10.1007/s10800-018-1174-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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12
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Tang B, Chen H, Peng H, Wang Z, Huang W. Graphene Modified TiO₂ Composite Photocatalysts: Mechanism, Progress and Perspective. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E105. [PMID: 29439545 PMCID: PMC5853736 DOI: 10.3390/nano8020105] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 11/17/2022]
Abstract
Graphene modified TiO₂ composite photocatalysts have drawn increasing attention because of their high performance. Some significant advancements have been achieved with the continuous research, such as the corresponding photocatalytic mechanism that has been revealed. Specific influencing factors have been discovered and potential optimizing methods are proposed. The latest developments in graphene assisted TiO₂ composite photocatalysts are abstracted and discussed. Based on the primary reasons behind the observed phenomena of these composite photocatalysts, probable development directions and further optimizing strategies are presented. Moreover, several novel detective technologies-beyond the decomposition test-which can be used to judge the photocatalytic performances of the resulting photocatalysts are listed and analyzed. Although some objectives have been achieved, new challenges still exist and hinder the widespread application of graphene-TiO₂ composite photocatalysts, which deserves further study.
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Affiliation(s)
- Bo Tang
- School of Petroleum Engineering, Changzhou University, Changzhou 213016, China.
| | - Haiqun Chen
- School of Petroleum Engineering, Changzhou University, Changzhou 213016, China.
| | - Haoping Peng
- School of Petroleum Engineering, Changzhou University, Changzhou 213016, China.
| | - Zhengwei Wang
- School of Petroleum Engineering, Changzhou University, Changzhou 213016, China.
| | - Weiqiu Huang
- School of Petroleum Engineering, Changzhou University, Changzhou 213016, China.
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Lemaire PC, King M, Parsons GN. Understanding inherent substrate selectivity during atomic layer deposition: Effect of surface preparation, hydroxyl density, and metal oxide composition on nucleation mechanisms during tungsten ALD. J Chem Phys 2017; 146:052811. [DOI: 10.1063/1.4967811] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Paul C. Lemaire
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Mariah King
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Gregory N. Parsons
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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Murphy M, Walczak M, Thomas A, Silikas N, Berner S, Lindsay R. Toward optimizing dental implant performance: Surface characterization of Ti and TiZr implant materials. Dent Mater 2017; 33:43-53. [DOI: 10.1016/j.dental.2016.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/29/2016] [Accepted: 10/09/2016] [Indexed: 01/05/2023]
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15
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Sachs M, Gellert M, Chen M, Drescher HJ, Kachel SR, Zhou H, Zugermeier M, Gorgoi M, Roling B, Gottfried JM. LiNi(0.5)Mn(1.5)O4 high-voltage cathode coated with Li4Ti5O12: a hard X-ray photoelectron spectroscopy (HAXPES) study. Phys Chem Chem Phys 2016; 17:31790-800. [PMID: 26563554 DOI: 10.1039/c5cp03837e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Li4Ti5O12 (LTO) film was coated as buffer layer onto a LiNi0.5Mn1.5O4 (LNMO) high-voltage cathode, and after cycling of the cathode in a battery electrolyte, the LTO film was investigated by means of synchrotron radiation based hard X-ray photoelectron spectroscopy (HAXPES). By tuning the photon energy between 2 keV and 6 keV, we obtained non-destructive depth profiles of the coating material with probing depths ranging from 6 nm to 20 nm. The coating was found to be covered by a few nanometers thin surface layer resulting from electrolyte decomposition. This layer consisted predominantly of organic polymers as well as metal fluorides and fluorophosphates. A positive influence of the Li4Ti5O12 coating with regard to the size and stability of the surface layer was found. The coating itself consisted of a uniform mixture of Li(I), Ti(IV), Ni(II) and Mn(IV) oxides that most likely adopted a spinel structure by forming a solid solution of the two spinels LiNi0.5Mn1.5O4 and Li4Ti5O12 with Li, Mn, Ni and Ti cations mixing on the spinel octahedral sites. The diffusion of Ni and Mn ions into the Li4Ti5O12 lattice occurred during the heat treatment when preparing the cathode. The doping of Li4Ti5O12 with the open d-shell ions Ni(2+) (d(8)) and Mn(4+) (d(3)) should increase the electronic conductivity of the coating significantly, as was found in previous studies. The complex signal structure of the Ti 2p, Ni 2p and Mn 2p core levels provides insight into the chemical nature of the transition metal ions.
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Affiliation(s)
- Malte Sachs
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Michael Gellert
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Min Chen
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Hans-Jörg Drescher
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Stefan Renato Kachel
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Han Zhou
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Malte Zugermeier
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - Mihaela Gorgoi
- Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Bernhard Roling
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
| | - J Michael Gottfried
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany.
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Henegar AJ, Cook AJ, Dang P, Gougousi T. Native Oxide Transport and Removal During Atomic Layer Deposition of TiO2 Films on GaAs(100) Surfaces. ACS APPLIED MATERIALS & INTERFACES 2016; 8:1667-1675. [PMID: 26741279 DOI: 10.1021/acsami.5b08998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, we studied the evolution and transport of the native oxides during the atomic layer deposition (ALD) of TiO2 on GaAs(100) from tetrakis dimethyl amino titanium and H2O. Arsenic oxide transport through the TiO2 film and removal during the ALD process was investigated using transmission Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Experiments were designed to decouple these processes by utilizing their temperature dependence. A 4 nm TiO2 layer was initially deposited on a native oxide surface at 100 °C. Ex situ XPS confirmed that this step disturbed the interface minimally. An additional 3 nm TiO2 film was subsequently deposited at 150 to 250 °C with and without an intermediate thermal treatment step at 250 °C. Arsenic and gallium oxide removal was confirmed during this second deposition, leading to the inevitable conclusion that these oxides traversed at least 4 nm of film so as to react with the precursor and its surface reaction/decomposition byproducts. XPS measurements confirmed the relocation of both arsenic and gallium oxides from the interface to the bulk of the TiO2 film under normal processing conditions. These results explain the continuous native oxide removal observed for alkyl-amine precursor-based ALD processes on III-V surfaces and provide further insight into the mechanisms of film growth.
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Affiliation(s)
- Alex J Henegar
- Department of Physics, UMBC , Baltimore, Maryland 21250, United States
| | - Andrew J Cook
- Department of Physics, UMBC , Baltimore, Maryland 21250, United States
| | - Phillip Dang
- Department of Physics, UMBC , Baltimore, Maryland 21250, United States
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17
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Duncan DA, Pfisterer JHK, Deimel PS, Acres RG, Fritton M, Feulner P, Barth JV, Allegretti F. Formation of a thermally stable bilayer of coadsorbed intact and deprotonated thymine exploiting the surface corrugation of rutile TiO2(110). Phys Chem Chem Phys 2016; 18:20433-42. [DOI: 10.1039/c6cp02541b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Adsorption of thymine on rutile TiO2(110) leads to a room temperature stable bilayer which follows the corrugation of the oxide surface and consists of both intact and deprotonated molecules.
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Affiliation(s)
- D. A. Duncan
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
- Diamond Light Source
| | - J. H. K. Pfisterer
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
| | - P. S. Deimel
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
| | - R. G. Acres
- Elettra-Sincrotrone Trieste
- 34149 Basovizza
- Italy
| | | | - P. Feulner
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
| | - J. V. Barth
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
| | - F. Allegretti
- Physik-Department E20
- Technische Universität München
- D-85748 Garching
- Germany
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18
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X-ray photoelectron spectroscopy of transition metal ions attached to the surface of rod-shape anatase TiO2 nanocrystals. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Atomistic modeling of peptide adsorption on rutile (100) in the presence of water and of contamination by low molecular weight alcohols. Biointerphases 2014; 9:031006. [DOI: 10.1116/1.4883555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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20
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Ruzicka JY, Bakar FA, Thomsen L, Cowie BC, McNicoll C, Kemmitt T, Brand HEA, Ingham B, Andersson GG, Golovko VB. XPS and NEXAFS study of fluorine modified TiO2 nano-ovoids reveals dependence of Ti3+ surface population on the modifying agent. RSC Adv 2014. [DOI: 10.1039/c3ra47652a] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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21
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Mattsson A, Lejon C, Bakardjieva S, Štengl V, Österlund L. Characterisation, phase stability and surface chemical properties of photocatalytic active Zr and Y co-doped anatase TiO2 nanoparticles. J SOLID STATE CHEM 2013. [DOI: 10.1016/j.jssc.2012.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Qualitative Analysis (Principle and Spectral Interpretation). SPRINGER SERIES IN SURFACE SCIENCES 2013. [DOI: 10.1007/978-3-642-27381-0_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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23
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Radović M, Salluzzo M, Ristić Z, Di Capua R, Lampis N, Vaglio R, Granozio FM. In situ investigation of the early stage of TiO2 epitaxy on (001) SrTiO3. J Chem Phys 2011; 135:034705. [DOI: 10.1063/1.3613637] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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24
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25
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Tunc I, Bruns M, Gliemann H, Grunze M, Koelsch P. Bandgap determination and charge separation in Ag@TiO2
core shell nanoparticle films. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3558] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Quah EL, Wilson JN, Idriss H. Photoreaction of the rutile TiO2(011) single-crystal surface: reaction with acetic acid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6411-6417. [PMID: 20187649 DOI: 10.1021/la9040985] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The reaction of acetic acid with stoichiometric and reduced rutile TiO(2)(011) single-crystal surfaces has been studied under dark and UV illumination conditions. The surface coverage after the dissociative adsorption of acetic acid with respect to Ti was found to be 0.55. Monitoring XPS Ti, O, and C lines revealed that the surface population decreased incrementally with temperature up to 650 K. The decrease in the slope of both the -CH(3)- and -COO- XPS peaks was not monotonic and followed two slopes in agreement with TPD results. The first channel involves the removal of surface acetates to acetic acid by recombinative desorption, and the second mainly involves dehydration to ketene. UV-light illumination was conducted at 300 K in the absence and presence of molecular oxygen at different pressures: in the 10(-6)-10(-9) Torr range. Acetate species were found to decrease with illumination time, and their decrease is seen to be dependent on the oxygen pressure. Plausible decomposition pathways are presented. Deliberately reducing the surface by electron bombardment prior to the adsorption of acetic acid did not affect the photoreaction rate within the experimental limits.
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Affiliation(s)
- E L Quah
- Department of Chemistry, The University of Auckland, Auckland, New Zealand
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27
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Jin H, Yoshikawa H, Tanuma S, Tougaard S. Energy loss function for Si determined from reflection electron energy loss spectra with factor analysis method. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Franking RA, Landis EC, Hamers RJ. Highly stable molecular layers on nanocrystalline anatase TiO2 through photochemical grafting. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10676-10684. [PMID: 19670904 DOI: 10.1021/la901116c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Well-defined molecular layers can be formed on the surface of nanocrystalline anatase TiO2 by photochemically grafting organic molecules bearing a terminal vinyl group. The molecular layers produced are shown to have minimal oxidation and are able to be patterned and uniformly grafted through optically thick nanocrystalline films. Stability tests show that the layers have excellent stability in deionized water at 80 degrees C, aqueous solutions at pH=1.0 and pH=10.3 at 65 degrees C, and acetonitrile for time scales approaching 1200 h. Degradation of the films in deionized water occurs using a AM1.5 full-spectrum solar simulator as an illumination source but is partially suppressed by filtering with a 400 nm UV blocking filter which blocks the above-bandgap light. A mechanism is proposed for the grafting reaction in which the surface hydroxyl groups trap photoexcited holes, facilitating reaction with the vinyl group.
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Affiliation(s)
- Ryan A Franking
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
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29
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Nomoto T, Onishi H. Fourth-order Raman spectroscopy of adsorbed organic species on TiO2 surface. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Pauly N, Tougaard S. Calculation of the angular distribution of the surface excitation parameter for Ti, Fe, Cu, Pd, Ag, and Au. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2650] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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de la Cruz W, Yubero F. Electron inelastic mean free paths: influence of the modelling energy-loss function. SURF INTERFACE ANAL 2007. [DOI: 10.1002/sia.2545] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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32
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Kövér L, Powell CJ. Report on the 42nd IUVSTA workshop ‘Electron scattering in solids: from fundamental concepts to practical applications’. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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33
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Zubkov T, Stahl D, Thompson TL, Panayotov D, Diwald O, Yates JT. Ultraviolet Light-Induced Hydrophilicity Effect on TiO2(110)(1×1). Dominant Role of the Photooxidation of Adsorbed Hydrocarbons Causing Wetting by Water Droplets. J Phys Chem B 2005; 109:15454-62. [PMID: 16852960 DOI: 10.1021/jp058101c] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The UV photoproduction of a hydrophilic TiO(2)(110)(1x1) surface has been investigated in a pressurized ultrahigh vacuum apparatus under controlled conditions of hydrocarbon concentration in oxygen gas at 1 atm pressure. Water droplet contact angles have been measured continuously as the droplet is exposed to UV irradiation, yielding the first observations of a sudden wetting process during irradiation. Using hexane as a model hydrocarbon, it is found that when low partial pressures of hexane are present, the sudden onset of surface wetting occurs during UV irradiation after an induction period under photooxidation conditions. The induction period to reach the critical condition for sudden wetting increases when the partial pressure (and equilibrium surface coverage) of hexane is increased. These results indicate that the removal of adsorbed hydrocarbons by photooxidation is the critical factor leading to the UV-induced hydrophilicity phenomenon on TiO(2). The phenomenon does not occur in the absence of O(2) gas. A concept concerned with kinetic screening of the TiO(2)-H(2)O interface from O(2) by water droplets is presented to explain the observation of sudden wetting in our experiments, compared to gradual wetting which is observed following UV irradiation in all other experiments reported in the literature. Complementary infrared spectroscopy measurements of the effect of UV irradiation in an O(2) atmosphere on adsorbed Ti-OH groups and on adsorbed H(2)O on the surface of a high-area TiO(2) powder show that no spectroscopic changes occur. This indicates that UV-induced changes in the -OH coverage or the nature of -OH bonding to TiO(2), as suggested by others, cannot be used to explain the photoinduced hydrophilicity effect.
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Affiliation(s)
- Tykhon Zubkov
- Surface Science Center, Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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34
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Prieto P, Hofmann S, Elizalde E, Sanz JM. Variation of the electron inelastic mean free path during depth profiling of the Fe/Si interface as determined by quantitative REELS. SURF INTERFACE ANAL 2004. [DOI: 10.1002/sia.1930] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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