1
|
Steele BA, Bastea S, Kuo IFW. Ab initio structural dynamics of pure and nitrogen-containing amorphous carbon. Sci Rep 2023; 13:19657. [PMID: 37951996 PMCID: PMC10640601 DOI: 10.1038/s41598-023-46642-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023] Open
Abstract
Amorphous carbon (a-C) has attracted considerable interest due to its desirable properties, which are strongly dependent on its structure, density and impurities. Using ab initio molecular dynamics simulations we show that the sp2/sp3 content and underlying structural order of a-C produced via liquid quenching evolve at high temperatures and pressures on sub-nanosecond timescales. Graphite-like densities ([Formula: see text] 2.7 g/cc) favor the formation of layered arrangements characterized by sp2 disordered bonding resembling recently synthesized monolayer amorphous carbon (MAC), while at diamond-like densities ([Formula: see text] 3.3 g/cc) the resulting structures are dominated by disordered tetrahedral sp3 hybridization typical of diamond-like amorphous carbon (DLC). At intermediate densities the system is a highly compressible mixture of coexisting sp2 and sp3 regions that continue to segregate over 10's of picoseconds. The addition of nitrogen (20.3%) (a-CN) generates major system features similar with those of a-C, but has the unexpected effect of reinforcing the thermodynamically disfavored carbon structural motifs at low and high densities, while inhibiting phase separation in the intermediate region. At the same time, no nitrogen elimination from the carbon framework is observed above [Formula: see text] 2.8 g/cc, suggesting that nitrogen impurities are likely to remain embedded in the carbon structures during fast temperature quenches at high pressures.
Collapse
Affiliation(s)
- Brad A Steele
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, 7000 East Ave., Livermore, California, 94550, USA
| | - Sorin Bastea
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, 7000 East Ave., Livermore, California, 94550, USA.
| | - I-Feng W Kuo
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, 7000 East Ave., Livermore, California, 94550, USA
| |
Collapse
|
2
|
Mocci F, de Villiers Engelbrecht L, Olla C, Cappai A, Casula MF, Melis C, Stagi L, Laaksonen A, Carbonaro CM. Carbon Nanodots from an In Silico Perspective. Chem Rev 2022; 122:13709-13799. [PMID: 35948072 PMCID: PMC9413235 DOI: 10.1021/acs.chemrev.1c00864] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carbon nanodots (CNDs) are the latest and most shining rising stars among photoluminescent (PL) nanomaterials. These carbon-based surface-passivated nanostructures compete with other related PL materials, including traditional semiconductor quantum dots and organic dyes, with a long list of benefits and emerging applications. Advantages of CNDs include tunable inherent optical properties and high photostability, rich possibilities for surface functionalization and doping, dispersibility, low toxicity, and viable synthesis (top-down and bottom-up) from organic materials. CNDs can be applied to biomedicine including imaging and sensing, drug-delivery, photodynamic therapy, photocatalysis but also to energy harvesting in solar cells and as LEDs. More applications are reported continuously, making this already a research field of its own. Understanding of the properties of CNDs requires one to go to the levels of electrons, atoms, molecules, and nanostructures at different scales using modern molecular modeling and to correlate it tightly with experiments. This review highlights different in silico techniques and studies, from quantum chemistry to the mesoscale, with particular reference to carbon nanodots, carbonaceous nanoparticles whose structural and photophysical properties are not fully elucidated. The role of experimental investigation is also presented. Hereby, we hope to encourage the reader to investigate CNDs and to apply virtual chemistry to obtain further insights needed to customize these amazing systems for novel prospective applications.
Collapse
Affiliation(s)
- Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy,
| | | | - Chiara Olla
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Antonio Cappai
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Maria Francesca Casula
- Department
of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, IT 09123 Cagliari, Italy
| | - Claudio Melis
- Department
of Physics, University of Cagliari, I-09042 Monserrato, Italy
| | - Luigi Stagi
- Department
of Chemistry and Pharmacy, Laboratory of Materials Science and Nanotechnology, University of Sassari, Via Vienna 2, 07100 Sassari, Italy
| | - Aatto Laaksonen
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy,Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden,State Key
Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China,Centre
of Advanced Research in Bionanoconjugates and Biopolymers, PetruPoni Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda 41A, 700487 Iasi, Romania,Division
of Energy Science, Energy Engineering, Luleå
University of Technology, Luleå 97187, Sweden,
| | | |
Collapse
|
3
|
Dwivedi N, Balasubramanian K, Sahu R, Manna S, Banik S, Dhand C, Kumar R, Hashmi SAR, Srivastava AK, Saifullah MSM, Sankaranarayanan SKRS. Unusual High Hardness and Load-Dependent Mechanical Characteristics of Hydrogenated Carbon-Nitrogen Hybrid Films. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20220-20229. [PMID: 35451828 DOI: 10.1021/acsami.2c01508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mechanical components are exposed to a rigorous environment in a number of applications including engineering, aerospace, and automobiles. Thus, their service lifetime and reliability are always on the verge of risk. Protective coatings with high hardness are required to enhance their service lifetime and minimize the replacement cost and waste burden. Hydrogenated amorphous carbon including nitrogen-incorporated films, that are commonly deposited by plasma-enhanced chemical vapor deposition, are widely used for commercial protective coating applications. However, their mechanical hardness still falls into the moderate hard regime. This needs to be substantially enhanced for advanced applications. Here, we report the synthesis of very hard nanostructured hydrogenated carbon-nitrogen hybrid (n-C:H:N) films. The optimized n-C:H:N film displays a hardness of about 36 GPa, elastic modulus of 360 GPa, and reasonably good elastic recovery (ER) of 62.7%. The mechanical properties of n-C:H:N films are further tailored when nitrogen pressure is tuned during the growth. The realized remarkably improved mechanical properties are correlated with the films' structural properties and experimental growth conditions. We also conducted density functional theory calculations that show the trend for the elastic modulus of the amorphous carbon films with varying nitrogen concentrations matches well with experimentally measured values. Finally, we probed load-dependent mechanical properties of n-C:H:N films and found an anomalous behavior; some of the mechanical parameters, for instance, ER, reveal an irregular trend with indentation load, which we explain in the framework of the film-substrate composite concept. Overall, this work uncovers many unknown and exciting mechanical phenomena that could pave the way for new technological developments.
Collapse
Affiliation(s)
- Neeraj Dwivedi
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Karthik Balasubramanian
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Riya Sahu
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
| | - Sukriti Manna
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Suvo Banik
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Chetna Dhand
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rajeev Kumar
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - S A R Hashmi
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - A K Srivastava
- CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal 462026, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - M S M Saifullah
- Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Subramanian K R S Sankaranarayanan
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| |
Collapse
|
4
|
Zhang S, Li Z, Luo K, He J, Gao Y, Soldatov AV, Benavides V, Shi K, Nie A, Zhang B, Hu W, Ma M, Liu Y, Wen B, Gao G, Liu B, Zhang Y, Shu Y, Yu D, Zhou XF, Zhao Z, Xu B, Su L, Yang G, Chernogorova OP, Tian Y. Discovery of carbon-based strongest and hardest amorphous material. Natl Sci Rev 2022; 9:nwab140. [PMID: 35070330 PMCID: PMC8776544 DOI: 10.1093/nsr/nwab140] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/06/2021] [Accepted: 07/20/2021] [Indexed: 12/27/2022] Open
Abstract
Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp 2 and sp 3). Exploring new forms of carbon has been the eternal theme of scientific research. Herein, we report on amorphous (AM) carbon materials with a high fraction of sp 3 bonding recovered from compression of fullerene C60 under high pressure and high temperature, previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5-2.2 eV, comparable to that of widely used AM silicon. Comprehensive mechanical tests demonstrate that synthesized AM-III carbon is the hardest and strongest AM material known to date, and can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.
Collapse
Affiliation(s)
- Shuangshuang Zhang
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Zihe Li
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Kun Luo
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Julong He
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Yufei Gao
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Alexander V Soldatov
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Vicente Benavides
- Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå SE-97187, Sweden
| | - Kaiyuan Shi
- Key Laboratory of Photochemistry, Institute of Chemistry, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Anmin Nie
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Bin Zhang
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Wentao Hu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Mengdong Ma
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Yong Liu
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Bin Wen
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Guoying Gao
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Bing Liu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Yang Zhang
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Yu Shu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Dongli Yu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Xiang-Feng Zhou
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Zhisheng Zhao
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Bo Xu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Lei Su
- Key Laboratory of Photochemistry, Institute of Chemistry, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Guoqiang Yang
- Key Laboratory of Photochemistry, Institute of Chemistry, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Olga P Chernogorova
- Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Moscow 119334, Russia
| | - Yongjun Tian
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| |
Collapse
|
5
|
Structure and Characterization of Vacuum Arc Deposited Carbon Films—A Critical Overview. COATINGS 2022. [DOI: 10.3390/coatings12020109] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This critical overview analyzes the relations between deposition conditions and structure for hydrogen-free carbon films, prepared by vacuum arc deposition. The manifold of film structures can be roughly divided into graphitic, nanostructured and amorphous films. Their detailed characterization uses advantageously sp3 fraction, density, Raman peak ratio and the mechanical properties (Young’s modulus and hardness). Vacuum arc deposition is based on energetic beams of carbon ions, where the film growth is mainly determined by ion energy and surface temperature. Both parameters can be clearly defined in the case of energy-selected carbon ion deposition, which thus represents a suitable reference method. In the case of vacuum arc deposition, the relation of the external controllable parameters (especially bias voltage and bulk temperature) with the internal growth conditions is more complex, e.g., due to the broad energy distribution, due to the varying “natural” ion energy and due to the surface heating by the ion bombardment. Nevertheless, some general trends of the structural development can be extracted. They are critically discussed and summarized in a hypothetical structural phase diagram in the energy-temperature plane.
Collapse
|
6
|
Picollo F, Battiato A, Bosia F, Scaffidi Muta F, Olivero P, Rigato V, Rubanov S. Creation of pure non-crystalline diamond nanostructures via room-temperature ion irradiation and subsequent thermal annealing. NANOSCALE ADVANCES 2021; 3:4156-4165. [PMID: 36132848 PMCID: PMC9419479 DOI: 10.1039/d1na00136a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/08/2021] [Indexed: 06/16/2023]
Abstract
Carbon exhibits a remarkable range of structural forms, due to the availability of sp3, sp2 and sp1 chemical bonds. Contrarily to other group IV elements such as silicon and germanium, the formation of an amorphous phase based exclusively on sp3 bonds is extremely challenging due to the strongly favored formation of graphitic-like structures at room temperature and pressure. As such, the formation of a fully sp3-bonded carbon phase requires an extremely careful (and largely unexplored) definition of the pressure and temperature across the phase diagram. Here, we report on the possibility of creating full-sp3 amorphous nanostructures within the bulk crystal of diamond with room-temperature ion-beam irradiation, followed by an annealing process that does not involve the application of any external mechanical pressure. As confirmed by numerical simulations, the (previously unreported) radiation-damage-induced formation of an amorphous sp2-free phase in diamond is determined by the buildup of extremely high internal stresses from the surrounding lattice, which (in the case of nanometer-scale regions) fully prevent the graphitization process. Besides the relevance of understanding the formation of exotic carbon phases, the use of focused/collimated ion beams discloses appealing perspectives for the direct fabrication of such nanostructures in complex three-dimensional geometries.
Collapse
Affiliation(s)
- F Picollo
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - A Battiato
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - F Bosia
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- Applied Science and Technology Department, Politecnico di Torino Torino 10129 Italy
| | - F Scaffidi Muta
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
| | - P Olivero
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - V Rigato
- National Institute of Nuclear Physics, National Laboratories of Legnaro Legnaro 35020 Italy
| | - S Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne Victoria 3010 Australia
| |
Collapse
|
7
|
Diamond-Like Carbon (DLC) Coatings: Classification, Properties, and Applications. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104445] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
DLC coatings have attracted an enormous amount of interest for science and engineering applications. DLC occurs in several different kinds of amorphous carbon materials. Owing to the extensive diversity in their properties, DLC coatings find applications in mechanical, civil, aerospace, automobile, biomedical, marine, and several other manufacturing industries. The coating life of DLC is predominately influenced by its constituent elements and manufacturing techniques. Numerous researchers have performed multiple experiments to achieve a robust understanding of DLC coatings and their inherent capabilities to enhance the life of components. In this review, a wide range of DLC coatings and their classification, properties, and applications are presented. Their remarkable performance in various applications has made DLC coatings a promising alternative over traditional solitary-coating approaches.
Collapse
|
8
|
Kaulfuss F, Weihnacht V, Zawischa M, Lorenz L, Makowski S, Hofmann F, Leson A. Effect of Energy and Temperature on Tetrahedral Amorphous Carbon Coatings Deposited by Filtered Laser-Arc. MATERIALS 2021; 14:ma14092176. [PMID: 33922873 PMCID: PMC8122976 DOI: 10.3390/ma14092176] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 11/29/2022]
Abstract
In this study, both the plasma process of filtered laser-arc evaporation and the resulting properties of tetrahedral amorphous carbon coatings are investigated. The energy distribution of the plasma species and the arc spot dynamics during the arc evaporation are described. Different ta-C coatings are synthesized by varying the bias pulse time and temperature during deposition. An increase in hardness was observed with the increased overlapping of the bias and arc pulse times. External heating resulted in a significant loss of hardness. A strong discrepancy between the in-plane properties and the properties in the film normal direction was detected specifically for a medium temperature of 120 °C during deposition. Investigations using electron microscopy revealed that this strong anisotropy can be explained by the formation of nanocrystalline graphite areas and their orientation toward the film’s normal direction. This novel coating type differs from standard amorphous a-C and ta-C coatings and offers new possibilities for superior mechanical behavior due to its combination of a high hardness and low in-plane Young’s Modulus.
Collapse
Affiliation(s)
- Frank Kaulfuss
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
- Correspondence: ; Tel.: +49-351-83391-3414
| | - Volker Weihnacht
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
| | - Martin Zawischa
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
| | - Lars Lorenz
- Institute of Manufacturing Science and Engineering, Technische Universität Dresden, 01069 Dresden, Germany;
| | - Stefan Makowski
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
| | - Falko Hofmann
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
| | - Andreas Leson
- Fraunhofer Institute for Material and Beam Technology (IWS), 01277 Dresden, Germany; (V.W.); (M.Z.); (S.M.); (F.H.); (A.L.)
| |
Collapse
|
9
|
Abstract
Amorphous carbons are disordered carbons with densities of circa 1.9–3.1 g/cc and a mixture of sp2 and sp3 hybridization. Using molecular dynamics simulations, we simulate diffusion in amorphous carbons at different densities and temperatures to investigate the transition between amorphous carbon and the liquid state. Arrhenius plots of the self-diffusion coefficient clearly demonstrate that there is a glass transition rather than a melting point. We consider five common carbon potentials (Tersoff, REBO-II, AIREBO, ReaxFF and EDIP) and all exhibit a glass transition. Although the glass-transition temperature (Tg) is not significantly affected by density, the choice of potential can vary Tg by up to 40%. Our results suggest that amorphous carbon should be interpreted as a glass rather than a solid.
Collapse
|
10
|
Zhang X, Hayashida R, Tanaka M, Watanabe T. Synthesis of carbon-coated silicon nanoparticles by induction thermal plasma for lithium ion battery. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2020.05.084] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
11
|
Park H, Woo D, Lee JM, Park SJ, Lee S, Kim HJ, Yoon E, Lee GD. The influence of hydrogen concentration in amorphous carbon films on mechanical properties and fluorine penetration: a density functional theory and ab initio molecular dynamics study. RSC Adv 2020; 10:6822-6830. [PMID: 35493897 PMCID: PMC9049780 DOI: 10.1039/c9ra09328a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 01/30/2020] [Indexed: 11/21/2022] Open
Abstract
Amorphous carbon (a-C) films have attracted significant attention due to their reliable structures and superior mechanical, chemical and electronic properties, making them a strong candidate as an etch hard mask material for the fabrication of future integrated semiconductor devices. Density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations were performed to investigate the energetics, structure, and mechanical properties of the a-C films with an increasing sp3 content by adjusting the atomic density or hydrogen content. A drastic increase in the bulk modulus is observed by increasing the atomic density of the a-C films, which suggests that it would be difficult for the films hardened by high atomic density to relieve the stress of the individual layers within the overall stack in integrated semiconductor devices. However, the addition of hydrogen into the a-C films has little effect on increasing the bulk modulus even though the sp3 content increases. For the F blocking nature, the change in the sp3 content by both atomic density and H concentration makes the diffusion barrier against the F atom even higher and suppresses the F diffusion, indicating that the F atom would follow the diffusion path passing through the sp2 carbon and not the sp3 carbon due to the significantly high barrier. For the material design of a-C films with adequate doped characteristics, our results can provide a new straightforward strategy to tailor the a-C films with excellent mechanical and other novel physical and chemical properties.
Collapse
Affiliation(s)
- Hwanyeol Park
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
- Memory Thin Film Technology Team, Giheung Hwaseong Complex, Samsung Electronics 445-701 South Korea
| | - Daekwang Woo
- Memory Thin Film Technology Team, Giheung Hwaseong Complex, Samsung Electronics 445-701 South Korea
| | - Jong Myeong Lee
- Memory Thin Film Technology Team, Giheung Hwaseong Complex, Samsung Electronics 445-701 South Korea
| | - Se Jun Park
- Memory Thin Film Technology Team, Giheung Hwaseong Complex, Samsung Electronics 445-701 South Korea
| | - Sungwoo Lee
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
| | - Ho Jun Kim
- Department of Mechanical Engineering, Dong-A University Busan 49315 South Korea
| | - Euijoon Yoon
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
- Research Institute of Advanced Materials, Inter-university Semiconductor Research Center, Seoul National University Seoul 08826 South Korea
| | - Gun-Do Lee
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
- Research Institute of Advanced Materials, Inter-university Semiconductor Research Center, Seoul National University Seoul 08826 South Korea
| |
Collapse
|
12
|
Fluorescence and Physico-Chemical Properties of Hydrogenated Detonation Nanodiamonds. C — JOURNAL OF CARBON RESEARCH 2020. [DOI: 10.3390/c6010007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Hydrogenated detonation nanodiamonds are of great interest for emerging applications in areas from biology and medicine to lubrication. Here, we compare the two main hydrogenation techniques—annealing in hydrogen and plasma-assisted hydrogenation—for the creation of detonation nanodiamonds with a hydrogen terminated surface from the same starting material. Synchrotron-based soft X-ray spectroscopy, infrared absorption spectroscopy, and electron energy loss spectroscopy were employed to quantify diamond and non-diamond carbon contents and determine the surface chemistries of all samples. Dynamic light scattering was used to study the particles’ colloidal properties in water. For the first time, steady-state and time-resolved fluorescence spectroscopy analysis at temperatures from room temperature down to 10 K was performed to investigate the particles’ fluorescence properties. Our results show that both hydrogenation techniques produce hydrogenated detonation nanodiamonds with overall similar physico-chemical and fluorescence properties.
Collapse
|
13
|
Liu J, Muíños HV, Nordlund K, Djurabekova F. Structural properties of protective diamond-like-carbon thin films grown on multilayer graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:505703. [PMID: 31476739 DOI: 10.1088/1361-648x/ab4094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In spite of the versatility of electronic properties of graphene, its fragility and low resistance to damage and external deformations reduce the practical value of this material for many applications. Coating of graphene with a thin layer of hard amorphous carbon is considered as a viable solution to protect the 2D material against accidental scratches and other external damaging impacts. In this study, we investigate the relationship between the deposition condition and quality of diamond-like-carbon (DLC) on top of multilayer graphene by means of molecular dynamics simulations. Deposition of carbon atoms with 70 eV incident energy at 100 K resulted in the highest content of [Formula: see text]-bonded C atoms. An increase of the number of dangling bonds at the interface between the top graphene layer and the DLC film indicates that decrease of the incident energy reduces the adhesion quality of DLC thin film on graphene. Analysis of radial distribution function indicates that [Formula: see text] hybridized carbon atoms tend to grow near already existing [Formula: see text]-atoms. This explains why the quality of the DLC structures grown on graphene have generally a lower content of [Formula: see text] C atoms compared to those grown directly on diamond. Ring analysis further shows that a DLC structure grown on the [Formula: see text]-rich structures like graphene contains a higher fraction of disordered ring structures.
Collapse
Affiliation(s)
- Jian Liu
- Helsinki Institute of Physics and Department of Physics, University of Helsinki, POB 43, 00014, Helsinki, Finland. Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
| | | | | | | |
Collapse
|
14
|
Soltanahmadi S, Charpentier T, Nedelcu I, Khetan V, Morina A, Freeman HM, Brown AP, Brydson R, van Eijk MCP, Neville A. Surface Fatigue Behavior of a WC/aC:H Thin-Film and the Tribochemical Impact of Zinc Dialkyldithiophosphate. ACS APPLIED MATERIALS & INTERFACES 2019; 11:41676-41687. [PMID: 31609570 DOI: 10.1021/acsami.9b14669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In wind turbine gearboxes, (near-)surface initiated fatigue is attributed to be the primary failure mechanism. In this work, the surface fatigue of a hydrogenated tungsten carbide/amorphous carbon (WC/aC:H) thin-film was tested under severe cyclic tribo-contact using polyalphaolefin (PAO) and PAO + zinc dialkyldithiophosphate (ZDDP) lubricants. The film was characterized in terms of its structure and chemistry using X-ray diffraction, analytical transmission electron microscopy, including electron energy loss spectroscopy (EELS), as well as X-ray photoelectron spectroscopy (XPS). The multilayer carbon thin-film exhibited promising surface fatigue performance showing a slight change in the hybridization state of the aC:H matrix. Dehydrogenation of the thin-film and subsequent transformation of cleaved C-H bonds to nonplanar sp2 carbon rings were inferred from EELS and XPS results. While tribo-induced changes to the aC:H matrix were not influenced by a nanometer-thick ZDDP reaction-film, the rate of oxidation of WC and its oxidation state were affected. While accelerating surface fatigue on a steel surface, the ZDDP-tribofilm protected the WC/aC:H film from surface fatigue. In contrast to the formation of polyphosphates from ZDDP molecules on steel surfaces, it appeared that on the WC/aC:H thin film surface, ZDDP molecules decompose to ZnO, suppressing the oxidative degradation of WC.
Collapse
Affiliation(s)
- Siavash Soltanahmadi
- iFS, School of Mechanical Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Thibaut Charpentier
- School of Chemical and Process Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Ileana Nedelcu
- SKF Research & Technology Development , 3430 DT Nieuwegein , The Netherlands
| | - Vishal Khetan
- iFS, School of Mechanical Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Ardian Morina
- iFS, School of Mechanical Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Helen M Freeman
- School of Chemical and Process Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Andrew P Brown
- School of Chemical and Process Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Rik Brydson
- School of Chemical and Process Engineering , University of Leeds , Leeds LS2 9JT , U.K
| | - Marcel C P van Eijk
- SKF Research & Technology Development , 3430 DT Nieuwegein , The Netherlands
| | - Anne Neville
- iFS, School of Mechanical Engineering , University of Leeds , Leeds LS2 9JT , U.K
| |
Collapse
|
15
|
Abstract
Machine-tool life is one limiting factor affecting productivity. The requirement for wear-resistant materials for cutting tools to increase their longevity is therefore critical. Titanium diboride (TiB2) coated cutting tools have been successfully employed for machining of AlSi alloys widely used in the automotive industry. This paper presents a methodological approach to improving the self-lubricating properties within the cutting zone of a tungsten carbide milling insert precoated with TiB2, thereby increasing the operational life of the tool. A unique hybrid Physical Vapor Deposition (PVD) system was used in this study, allowing diamond-like carbon (DLC) to be deposited by filtered cathodic vacuum arc (FCVA) while PVD magnetron sputtering was employed to deposit WS2. A series of ~100-nm monolayer DLC coatings were prepared at a negative bias voltage ranging between −50 and −200 V, along with multilayered DLC-WS2 coatings (total thickness ~500 nm) with varying number of layers (two to 24 in total). The wear rate of the coated milling inserts was investigated by measuring the flank wear during face milling of an Al-10Si. It was ascertained that employing monolayer DLC coating reduced the coated tool wear rate by ~85% compared to a TiB2 benchmark. Combining DLC with WS2 as a multilayered coating further improved tool life. The best tribological properties were found for a two-layer DLC-WS2 coating which decreased wear rate by ~75% compared to TiB2, with a measured coefficient of friction of 0.05.
Collapse
|
16
|
Li X, Wang A, Lee K. Tribo‐Induced Structural Transformation and Lubricant Dissociation at Amorphous Carbon–Alpha Olefin Interface. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800157] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xiaowei Li
- Computational Science CenterKorea Institute of Science and Technology Seoul 136–791 Republic of Korea
- Key Laboratory of Marine Materials and Related TechnologiesZhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Ningbo 315201 P. R. China
| | - Aiying Wang
- Key Laboratory of Marine Materials and Related TechnologiesZhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Ningbo 315201 P. R. China
| | - Kwang‐Ryeol Lee
- Computational Science CenterKorea Institute of Science and Technology Seoul 136–791 Republic of Korea
| |
Collapse
|
17
|
Papaioannou N, Marinovic A, Yoshizawa N, Goode AE, Fay M, Khlobystov A, Titirici MM, Sapelkin A. Structure and solvents effects on the optical properties of sugar-derived carbon nanodots. Sci Rep 2018; 8:6559. [PMID: 29700398 PMCID: PMC5920085 DOI: 10.1038/s41598-018-25012-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 04/12/2018] [Indexed: 11/29/2022] Open
Abstract
Carbon nanodots are a new and intriguing class of fluorescent carbon nanomaterials and are considered a promising low cost, nontoxic alternative to traditional inorganic quantum dots in applications such as bioimaging, solar cells, photocatalysis, sensors and others. Despite the abundant available literature, a clear formation mechanism for carbon nanodots prepared hydrothermally from biomass precursors along with the origins of the light emission are still under debate. In this paper, we investigate the relationships between the chemical structure and optical properties of carbon nanodots prepared by the hydrothermal treatment of glucose. Our major finding is that the widely reported excitation-dependent emission originates from solvents used to suspend the as-prepared carbon nanodots, while emission from dry samples shows no excitation-dependence. Another important highlight is that the hydrothermal conversion of biomass-derivatives under subcritical conditions leads to a heterogeneous mixture of amorphous-like nanoparticles, carbon onion-type and crystalline carbons composed of at least three different phases. The potential chemical reaction pathways involved in the formation of these hydrothermal carbon products along with a comprehensive structural and optical characterization of these systems is also provided.
Collapse
Affiliation(s)
- Nikolaos Papaioannou
- School of Physics and Astronomy, Queen Mary, University of London, 327 Mile End Road, London, E1 4NS, UK
- Materials Research Institute, Queen Mary University of London, Mile End Road, E14NS, London, UK
| | - Adam Marinovic
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, E1 4NS, London, UK
| | - Noriko Yoshizawa
- Electron Microscope Facility, TIA, AIST, 16-1 Onogawa, Tsukuba, 305-8569, Japan
| | - Angela E Goode
- Department of Materials, Faculty of Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Michael Fay
- Nanoscale and Microscale Research Centre, University of Nottingham, University Park, NG7 2RD, Nottingham, UK
| | - Andrei Khlobystov
- Nanoscale and Microscale Research Centre, University of Nottingham, University Park, NG7 2RD, Nottingham, UK
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Maria-Magdalena Titirici
- Materials Research Institute, Queen Mary University of London, Mile End Road, E14NS, London, UK.
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
| | - Andrei Sapelkin
- School of Physics and Astronomy, Queen Mary, University of London, 327 Mile End Road, London, E1 4NS, UK.
- Materials Research Institute, Queen Mary University of London, Mile End Road, E14NS, London, UK.
| |
Collapse
|
18
|
Takabayashi S, Okamoto K, Nakatani T. Influence of post-annealing on a diamondlike carbon film analyzed by Raman spectroscopy. SURF INTERFACE ANAL 2018. [DOI: 10.1002/sia.6387] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Susumu Takabayashi
- Research Institute of Electrical Communication; Tohoku University; 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter; Hiroshima University; 1-3-1 Kagamiyama, Higashihiroshima Hiroshima 739-8530 Japan
| | - Keishi Okamoto
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter; Hiroshima University; 1-3-1 Kagamiyama, Higashihiroshima Hiroshima 739-8530 Japan
- Toyo Advanced Technologies Co., Ltd.; 5-3-38 Ujina-Higashi, Minami-ku Hiroshima 734-8501 Japan
| | - Tatsuyuki Nakatani
- Toyo Advanced Technologies Co., Ltd.; 5-3-38 Ujina-Higashi, Minami-ku Hiroshima 734-8501 Japan
- Research Institute of Technology; Okayama University of Science; 1-1 Ridai-cho, Kita-ku Okayama 700-0005 Japan
| |
Collapse
|
19
|
Yeo RJ, Dwivedi N, Zhang L, Zhang Z, Lim CYH, Tripathy S, Bhatia CS. Superior wear resistance and low friction in hybrid ultrathin silicon nitride/carbon films: synergy of the interfacial chemistry and carbon microstructure. NANOSCALE 2017; 9:14937-14951. [PMID: 28952649 DOI: 10.1039/c7nr03737f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Amorphous carbon-based films are commonly investigated as protective nanocoatings in macro- to nano-scale devices due to their exceptional tribological and mechanical properties. However, with further device miniaturization where even thinner coatings are required, the wear durability of the nanocoating rapidly degrades at the expense of lower thickness. Here we discover that for sub-10 nm coating thicknesses, a hybrid bi-layer film structure, comprising a high sp3-bonded amorphous carbon top layer and a silicon nitride (SiNx) bottom layer, consistently outperforms its single-layer amorphous carbon counterpart in terms of wear durability on a commercial tape drive head, while exhibiting low, stable friction and excellent wear resistance on a flat ceramic substrate. The superior performance of the hybrid film is attributed to the constructive synergy of the sp3-rich carbon microstructure and an enhanced interfacial chemistry arising from additional interfacial bonding. Moreover, a high energy C+ ion treatment step, introduced either directly to the substrate or to the SiNx layer before carbon deposition, also aids in increasing atomic mixing that contributes to further improvement in the wear resistance. This study highlights the importance of both the carbon microstructure and interfacial chemistry in the design of wear-durable nanocoatings at few-nanometer thicknesses, particularly for aggressive wear conditions.
Collapse
Affiliation(s)
- Reuben J Yeo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583.
| | | | | | | | | | | | | |
Collapse
|
20
|
Lai CC, Goyenola C, Broitman E, Näslund LÅ, Högberg H, Hultman L, Gueorguiev GK, Rosen J. Synthesis and properties of CS x F y thin films deposited by reactive magnetron sputtering in an Ar/SF 6 discharge. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:195701. [PMID: 28319035 DOI: 10.1088/1361-648x/aa67d2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A theoretical and experimental study on the growth and properties of a ternary carbon-based material, CS x F y , synthesized from SF6 and C as primary precursors is reported. The synthetic growth concept was applied to model the possible species resulting from the fragmentation of SF6 molecules and the recombination of S-F fragments with atomic C. The possible species were further evaluated for their contribution to the film growth. Corresponding solid CS x F y thin films were deposited by reactive direct current magnetron sputtering from a C target in a mixed Ar/SF6 discharge with different SF6 partial pressures ([Formula: see text]). Properties of the films were determined by x-ray photoelectron spectroscopy, x-ray reflectivity, and nanoindentation. A reduced mass density in the CS x F y films is predicted due to incorporation of precursor species with a more pronounced steric effect, which also agrees with the low density values observed for the films. Increased [Formula: see text] leads to decreasing deposition rate and increasing density, as explained by enhanced fluorination and etching on the deposited surface by a larger concentration of F/F2 species during the growth, as supported by an increment of the F relative content in the films. Mechanical properties indicating superelasticity were obtained from the film with lowest F content, implying a fullerene-like structure in CS x F y compounds.
Collapse
Affiliation(s)
- Chung-Chuan Lai
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Hu C, Li W, Lin Q, Zheng X, Pan H, Huang Q. Impact of ferrocene on the nanostructure and functional groups of soot in a propane/oxygen diffusion flame. RSC Adv 2017. [DOI: 10.1039/c6ra26096a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ferrocene influences soot oxidation activity by changing its nanostructure and functional groups on the surface. Reactions between oxygen and ferrocene reduce the oxygen-containing functional groups on the soot.
Collapse
Affiliation(s)
- Chao Hu
- Department of Thermal Science and Energy Engineering
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Wenzhi Li
- Department of Thermal Science and Energy Engineering
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Qizhao Lin
- Department of Thermal Science and Energy Engineering
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Xusheng Zheng
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Haibin Pan
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| | - Qifu Huang
- Department of Thermal Science and Energy Engineering
- University of Science and Technology of China
- Hefei 230026
- People's Republic of China
| |
Collapse
|
22
|
Wilson M. Structure and dynamics in network-forming materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:503001. [PMID: 27779129 DOI: 10.1088/0953-8984/28/50/503001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The study of the structure and dynamics of network-forming materials is reviewed. Experimental techniques used to extract key structural information are briefly considered. Strategies for building simulation models, based on both targeting key (experimentally-accessible) materials and on systematically controlling key model parameters, are discussed. As an example of the first class of materials, a key target system, SiO2, is used to highlight how the changing structure with applied pressure can be effectively modelled (in three dimensions) and used to link to both experimental results and simple structural models. As an example of the second class the topology of networks of tetrahedra in the MX2 stoichiometry are controlled using a single model parameter linked to the M-X-M bond angles. The evolution of ordering on multiple length-scales is observed as are the links between the static structure and key dynamical properties. The isomorphous relationship between the structures of amorphous Si and SiO2 is discussed as are the similarities and differences in the phase diagrams, the latter linked to potential polyamorphic and 'anomalous' (e.g. density maxima) behaviour. Links to both two-dimensional structures for C, Si and Ge and near-two-dimensional bilayers of SiO2 are discussed. Emerging low-dimensional structures in low temperature molten carbonates are also uncovered.
Collapse
Affiliation(s)
- Mark Wilson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| |
Collapse
|
23
|
Ichimura S, Hayashi Y, Umeno M. Multilayer graphene/amorphous carbon hybrid films prepared by microwave surface-wave plasma CVD: synthesis and characterization. SURF INTERFACE ANAL 2016. [DOI: 10.1002/sia.6133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Susumu Ichimura
- Department of Electrical and Electronic Engineering; Okayama University; 2-1-1 Tsushima-naka, Kita-ku Okayama 700-8530 Japan
- Institute for General Research of Science; Chubu University; 1200 Matsumoto-cho Kasugai Aichi 487-8501 Japan
| | - Yasuhiko Hayashi
- Department of Electrical and Electronic Engineering; Okayama University; 2-1-1 Tsushima-naka, Kita-ku Okayama 700-8530 Japan
| | - Masayoshi Umeno
- Institute for General Research of Science; Chubu University; 1200 Matsumoto-cho Kasugai Aichi 487-8501 Japan
| |
Collapse
|
24
|
Su YF, Park JG, Koo A, Trayner S, Hao A, Downes R, Liang R. Characterization at Atomic Resolution of Carbon Nanotube/Resin Interface in Nanocomposites by Mapping sp 2-Bonding States Using Electron Energy-Loss Spectroscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:666-672. [PMID: 27329314 DOI: 10.1017/s1431927616000805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Functionalization is critical for improving mechanical properties of carbon nanotubes (CNTs)/polymer nanocomposites. A fundamental understanding of the role of the CNT/polymer interface and bonding structure is key to improving functionalization procedures for higher mechanical performance. In this study, we investigated the effects of chemical functionalization on the nanocomposite interface at atomic resolution to provide direct and quantifiable information of the interactions and interface formation between CNT surfaces and adjacent resin molecules. We observed and compared electronic structures and their changes at the interfaces of nonfunctionalized and functionalized CNT/polymer nanocomposite samples via scanning transmission electron microscopy and electron energy-loss spectroscopy (EELS) spectrum imaging techniques. The results show that the state of sp 2 bonding and its distribution at the CNT/resin interface can be clearly visualized through EELS mapping. We found that the functionalized CNT/polymer samples exhibited a lower fraction of sp 2 bonding and a lower π*/σ* ratio compared with the nonfunctionalized cases. A good correlation between near-edge fine structures and low-loss plasmon energies was observed.
Collapse
Affiliation(s)
- Yi-Feng Su
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Jin G Park
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Ana Koo
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Sarah Trayner
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Ayou Hao
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Rebekah Downes
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| | - Richard Liang
- National High Magnetic Field Laboratory,High-Performance Materials Institute,Florida State University,Tallahassee,FL 32310,USA
| |
Collapse
|
25
|
Mangolini F, McClimon JB, Carpick RW. Quantitative Evaluation of the Carbon Hybridization State by Near Edge X-ray Absorption Fine Structure Spectroscopy. Anal Chem 2016; 88:2817-24. [DOI: 10.1021/acs.analchem.5b04525] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Filippo Mangolini
- Institute
of Functional Surfaces, School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, U.K
| | - J. Brandon McClimon
- Department
of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Robert W. Carpick
- Department
of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| |
Collapse
|
26
|
Santos M, Bilek M, Wise S. Plasma-synthesised carbon-based coatings for cardiovascular applications. BIOSURFACE AND BIOTRIBOLOGY 2015. [DOI: 10.1016/j.bsbt.2015.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
27
|
Structural, nanomechanical, field emission and ammonia gas sensing properties of nitrogenated amorphous carbon films deposited by filtered anodic jet carbon arc technique. Talanta 2014; 125:276-83. [DOI: 10.1016/j.talanta.2014.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/26/2014] [Accepted: 03/05/2014] [Indexed: 11/20/2022]
|
28
|
Ito AM, Takayama A, Oda Y, Nakamura H. The First principle calculation of bulk modulus and Young's modulus for amorphous carbon material. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/518/1/012011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
29
|
Wasy A, Balakrishnan G, Lee SH, Kim JK, Kim DG, Kim TG, Song JI. Argon plasma treatment on metal substrates and effects on diamond-like carbon (DLC) coating properties. CRYSTAL RESEARCH AND TECHNOLOGY 2013. [DOI: 10.1002/crat.201300171] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Abdul Wasy
- Department of Mechanical Engineering; Changwon National University; Changwon-641773 Republic of Korea
| | - G. Balakrishnan
- Department of Mechanical Engineering; Changwon National University; Changwon-641773 Republic of Korea
- Centre for Materials Research; Bharath University; Chennai-600073 India
| | - S. H. Lee
- Surface Technology Division; Korea Institute of Materials Sciences; Changwon-642831 Republic of Korea
| | - J. K. Kim
- Surface Technology Division; Korea Institute of Materials Sciences; Changwon-642831 Republic of Korea
| | - D. G. Kim
- Surface Technology Division; Korea Institute of Materials Sciences; Changwon-642831 Republic of Korea
| | - T. G. Kim
- Department of Nanomechatronics Engineering; Pusan National University; Miryang-si-627706 Republic of Korea
| | - J. I. Song
- Department of Mechanical Engineering; Changwon National University; Changwon-641773 Republic of Korea
| |
Collapse
|
30
|
Larruquert JI, Rodríguez-de Marcos LV, Méndez JA, Martin PJ, Bendavid A. High reflectance ta-C coatings in the extreme ultraviolet. OPTICS EXPRESS 2013; 21:27537-27549. [PMID: 24514272 DOI: 10.1364/oe.21.027537] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The extreme ultraviolet (EUV) reflectance of amorphous tetrahedrally coordinated carbon films (ta-C) prepared by filtered cathodic vacuum arc was measured in the 30-188-nm range at near normal incidence. The measured reflectance of films grown with average ion energies in the ~70-140-eV range was significantly larger than the reflectance of a C film grown with average ion energy of ~20 eV and of C films deposited by sputtering or evaporation. The difference is attributed to a large proportion of sp3 atom bonding in the ta-C film. This high reflectance is obtained for films deposited onto room-temperature substrates. The reflectance of ta-C films is higher than the standard single-layer coating materials in the EUV spectral range below 130 nm. A self-consistent set of optical constants of ta-C films was obtained with the Kramers-Krönig analysis using ellipsometry measurements in the 190-950 nm range and the EUV reflectance measurements. These optical constants allowed calculating the EUV reflectance of ta-C films at grazing incidence for applications such as free electron laser mirrors.
Collapse
|
31
|
Robinson DR, Wilson M. The liquid<−>amorphous transition and the high pressure phase diagram of carbon. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:155101. [PMID: 23462588 DOI: 10.1088/0953-8984/25/15/155101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The phase diagram of carbon is mapped to high pressure using a computationally-tractable potential model. The use of a relatively simple (Tersoff-II) potential model allows a large range of phase space to be explored. The coexistence (melting) curve for the diamond crystal/liquid dyad is mapped directly by modelling the solid/liquid interfaces. The melting curve is found to be re-entrant and belongs to a conformal class of diamond/liquid coexistence curves. On supercooling the liquid a phase transition to a tetrahedral amorphous form (ta-C) is observed. The liquid <−> amorphous coexistence curve is mapped onto the pT plane and is found to also be re-entrant. The entropy changes for both melting and the amorphous −> liquid transitions are obtained from the respective coexistence curves and the associated changes in molar volume. The structural change on amorphization is analysed at different points on the coexistence curve including for transitions that are both isochoric and isocoordinate (no change in nearest-neighbour coordination number). The conformal nature of the melting curve is highlighted with respect to the known behaviour of Si. The relationship of the observed liquid/amorphous coexistence curve to the Si low- and high-density amorphous (LDA/HDA) transition is discussed.
Collapse
Affiliation(s)
- David R Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | | |
Collapse
|
32
|
Monteiro OR, Delplancke-Ogletree MP, Brown IG, Ager JW. Deposition and Properties of Doped Diamondlike Carbon Films Produced by Dual-Source Vacuum Arc Plasma Immersion. ACTA ACUST UNITED AC 2012. [DOI: 10.1557/proc-438-599] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractDiamond-like carbon films with mechanical properties approaching those of diamond have been consistently produced by cathodic vacuum arc based techniques. These films have been successfully used in applications where enhanced hardness and wear resistance are required Such DLC films have two major drawbacks that prevent their application in other areas: a high level of internal stresses, which promotes failure by spallation of thick films; and the loss of mechanical properties at temperatures higher than 300°C. In this paper we describe the effect of doping elements on the room-temperature mechanical properties and on the thermal stability of DLC films upon annealing in air. The effect of the presence of W and Ti was investigated and compared to pure DLC. The films were produced by dual-source metal plasma immersion ion implantation and deposition with magnetic filtering to remove macroparticles from the plasma; dopant content was controlled by varying the relative pulse duration of the two plasma sources. Microstructural and chemical characterization of the films are presented.
Collapse
|
33
|
Mathioudakis C, Fyta M. Disorder and optical gaps in strained dense amorphous carbon and diamond nanocomposites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:205502. [PMID: 22532117 DOI: 10.1088/0953-8984/24/20/205502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We employ empirical tight-binding simulations on strained tetrahedral amorphous carbon and diamond nanocomposite networks. For each applied strain, the optoelectronic properties are monitored through the absorption coefficient and the dielectric function. These lead to the optical gaps and are able to quantify the amount of disorder in the structures. We compare our results to those of unstrained nanostructured diamond and amorphous carbon (a-C) phases and link the degree of disorder in these materials to their structural details as a function of the external load. The atomic rearrangements and distortions imposed by the external strain in these structures are directly observable in their optoelectronic properties. We thoroughly discuss the interplay between increased external strain, structural and topological disorder, atomic rearrangements and their effect on the calculated optoelectronic properties.
Collapse
Affiliation(s)
- Christos Mathioudakis
- Department of Materials Science and Technology, University of Crete, Heraklion, Crete, Greece.
| | | |
Collapse
|
34
|
ZHANG S, BUI XL, FU Y, DU H. DEVELOPMENT OF CARBON-BASED COATING OF EXTREMELY HIGH TOUGHNESS WITH GOOD HARDNESS. INTERNATIONAL JOURNAL OF NANOSCIENCE 2011. [DOI: 10.1142/s0219581x04002395] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Metallic Al was doped into amorphous carbon (a-C) to form a matrix of a-C(Al) of very low residual stress and high toughness at the expense of some hardness. Nanocrystallites of TiC (nc-TiC) of a few nanometers in size were embedded in this matrix to bring back the hardness. The nanocomposite coating of nc-TiC/a-C(Al) was deposited via co-sputtering of graphite, Ti , and Al targets. Although the nanocomposite coating exhibited a moderately high hardness (about 20 GPa), it possessed extremely high toughness (about 55% of plasticity during indentation deformation) and low residual stress (less than 0.4 GPa), smooth (Ra=5.5 nm ), and hydrophobic surface (contact angle with water reaches 100°).
Collapse
Affiliation(s)
- S. ZHANG
- School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - X. L. BUI
- School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Y. FU
- School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - H. DU
- School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| |
Collapse
|
35
|
BRULEY J, WILLIAMS DB, CUOMO JJ, PAPPAS DP. Quantitative near-edge structure analysis of diamond-like carbon in the electron microscope using a two-window method. J Microsc 2011. [DOI: 10.1111/j.1365-2818.1995.tb03653.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
36
|
De Vriendt V, Miladinovic SM, Colaux JL, Maseri F, Wilkins CL, Lucas S. Growth mechanisms involved in the synthesis of smooth and microtextured films by acetylene magnetron discharges. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8913-8922. [PMID: 21692461 DOI: 10.1021/la2003035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges of acetylene (C(2)H(2)) in an unbalanced magnetron setup was investigated. At 5 × 10(-3) Torr, only smooth films are obtained, whereas at 5 × 10(-1) Torr using a pulsed discharge some microtextured films are formed if the duty cycle is low. The morphology of these microtextured films consists of nanoparticles, filamentary particles, and particular agglomerates ("microflowers"). This paper presents a study of acetylene gas phase polymerization by mass spectrometry, and a detailed analysis of bulk structure of films by combining three techniques which include IR spectroscopy, Raman spectroscopy, and laser desorption/ionization Fourier transform mass spectrometry (LDI-FTMS). Finally, based on the study of gas phase and film structure, we propose a model for the growth of both smooth and microtextured films.
Collapse
Affiliation(s)
- Valérie De Vriendt
- Research Center for the Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Namur, Belgium
| | | | | | | | | | | |
Collapse
|
37
|
Xu Z, Bando Y, Liu L, Wang W, Bai X, Golberg D. Electrical conductivity, chemistry, and bonding alternations under graphene oxide to graphene transition as revealed by in situ TEM. ACS NANO 2011; 5:4401-4406. [PMID: 21557542 DOI: 10.1021/nn103200t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A suspended graphene oxide device is fabricated and investigated using a transmission electron microscope (TEM) scanning tunneling microscope (STM) setup. A detailed study of step-by-step reduction of an individual graphene oxide sheet under current flow and Joule heating in tandem with conductivity measurements, atomic structure imaging, chemical composition, and bonding alternations tracing is performed. As monitored by electron energy loss spectroscopy, the oxygen content is tuned from that peculiar to a pristine graphene oxide (i.e., 23.8 at %) to oxygen-free pure graphene. Six orders of magnitude conductance rise is observed during this process with the final conductivity reaching 1.5 × 10(5) S/m. Quantification of plasma energy losses of the starting graphene oxide shows that ∼40% of the oxygen atoms are in the form of epoxy, and ∼60% oxygen atoms are in the form of hydroxyl. The total portion of sp(3) bonds in pristine graphene oxide is estimated to be ∼45%. The epoxy groups show a larger influence on the conductivity of graphene oxide than hydroxyl ones. Through analyzing consecutive plasma-loss energy spectra under gradual graphene oxide to graphene transformation, it is found that the oxygen atoms in epoxy groups decompose prior to those in hydroxyl groups.
Collapse
Affiliation(s)
- Zhi Xu
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | | | | | | | | | | |
Collapse
|
38
|
Dwivedi N, Kumar S, Malik HK, Rauthan CMS, Panwar OS. Role of Sandwich Cu Layer in and Effect of Self-Bias on Nanomechanical Properties of Copper/Diamond-Like Carbon Bilayer Films. ACTA ACUST UNITED AC 2011. [DOI: 10.5402/2011/846187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The role of sandwich Cu layer in and effect of self-bias on structural and nanomechanical properties of Cu/DLC bilayer films have been explored. Cu/DLC bilayer films were grown, under varied self-bias from −125 to −225 V, using hybrid system involving radio-frequency- (RF-) plasma-enhanced chemical vapor deposition and RF-sputtering units. Surface topography and mean roughness was studied by atomic force microscope and then correlated with mechanical properties. The addition of sandwich Cu layer in DLC reduces its residual stress and does not affect bilayer film hardness and elastic modulus. Load versus displacement was also employed to estimate various other mechanical parameters, which further correlated with self-bias and structural properties. These Cu/DLC bilayer films seem to be a potential candidate for various industrial applications such as hard and protective coating on cutting tools, solar cells, and wear resistance coating on magnetic storage media.
Collapse
Affiliation(s)
- Neeraj Dwivedi
- Physics of Energy Harvesting Division, National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110012, India
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 , India
| | - Sushil Kumar
- Physics of Energy Harvesting Division, National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110012, India
| | - Hitendra K. Malik
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 , India
| | - C. M. S. Rauthan
- Physics of Energy Harvesting Division, National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110012, India
| | - O. S. Panwar
- Physics of Energy Harvesting Division, National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110012, India
| |
Collapse
|
39
|
Anders A, Kulkarni AV. Synthesis of Ultrathin Ta-C Films by Twist-Filtered Cathodic Arc Carbon Plasmas. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-675-w11.1.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe application of cathodic-arc-deposited films has been very slow due to the infamous macroparticle problem. We report about the application of the open Twist Filter as the key component to an advanced filtered cathodic arc system. Ultrathin tetrahedral amorphous carbon (ta-C) films have been deposited on 6 inch wafers. Film propertieshave been investigated with respect to application in the magnetic data storage industry. Films can be deposited in a reproducible manner where film thickness control relies on arc pulse counting once deposition rates have been calibrated. Films of 3 nm thickness have been deposited that passed acid and Battelle corrosion tests. Monte Carlo Simulation of energetic carbon deposition shows the formation of an intermixed transition layer of about 1 nm. The simulation indicates that because the displacement energy of carbon isnot smaller than of magnetic materials, films thinner than 2 nm are either not high in sp3 content or represent a carbidic phase.
Collapse
|
40
|
Tanner BK, LiBassi A, Ferrari AC, Robertson J. X-Ray Reflectivity of Ultra-Thin Diamond-Like Carbon Films. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-675-w11.4.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTGrazing incidence x-ray reflectivity has been employed to investigate ultra-thin films of tetrahedral amorphous carbon (ta-C) grown with an S-bend filtered cathodic vacuum arc. The results indicate that x-ray reflectivity can be used as a metrological tool for thickness measurements on films as thin as 0.5 nm, which is lower than the range required for carbon overcoats for magnetic hard disks and sliders if they are to reach storage densities of 100 Gbits/in2. The density of the films was derived from the best-fit to simulated reflectivity profiles from models for the structural parameters. In such thin films, the x-rays are reflected mainly at the film substrate interface, rather than the outer surface, so that the film density is derived from analysisof the oscillations of the post-critical angle reflectivity.
Collapse
|
41
|
Satyanarayana B, Takahashi H, Narusawa T, Hiraki A. Effect of Metal Back Contacts on Tetrahedral Amorphous Carbonc Films Grown Using the Cathodic Arc Process. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-675-w10.2.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTReported here is a study on the effect of different metal back contacts onthe electrical and structural properties of the tetrahedral amorphous carbon (ta-C). The films were grown using a pulsed cathodic arc system. Ta-C films were deposited simultaneously on silicon substrate, precoated with the following metals, namely aluminium (Al), gold (Au), chromium(Cr), molybdenum (Mo), copper (Cu), tungsten (W) and titanium(Ti). The electrical measurements and Raman response show that the back contact does influence the properties of ta-C films. These results are analysed with respect to our earlier report regarding the influence of back contacts on field emission from similar ta-C films.
Collapse
|
42
|
hofsäss H, Biegel J, Ronning C, Downing R, Lamaze G. Characterization of Doped Diamondlike Carbon Films and Multilayers. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-316-881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTWe have grown doped diamondlike carbon (DLC) thin films on Ni and Si substrates by mass separated low energy ion beam deposition. The current-voltage characteristics of these films and also a P-doped DLC / B-doped DLC diode-like device were measured. Doped DLC films show a higher electrical conductivity, which we interpret by hopping conductivity due to an increased density of localized states rather than a shift of the Fermi level. We also present first results on doping modulated DLC multilayers deposited on Si substrates. The dopant concentration profiles were analyzed by Rutherford Backscattering for63Cu dopant atoms and by neutron depth profiling for a10B doped multilayer.
Collapse
|
43
|
Lowndes DH, Merkulov VI, Puretzky AA, Geohegan DB, Jellison GE, Rouleau CM, Thundat T. Amorphous Diamond Films Deposited by Pulsed-Laser Ablation: the Optimum Carbon-Ion Kinetic Energy and Effects of Laser Wavelength. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-526-325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractA systematic study has been made of changes in the bonding and optical properties of hydrogen-free tetrahedral amorphous carbon (ta-C) films, as a function of the kinetic energy of the incident carbon ions measured under film-deposition conditions. Ion probe measurements of the carbon ion kinetic energies produced by ArF and KrF laser ablation of graphite are compared under identical beam-focusing conditions. Much higher C+ kinetic energies are produced by ArF-laser ablation than by KrF for any given fluence and spot size. Electron energy loss spectroscopy and scanning ellipsometry measurements of the sp3 bonding fraction, plasmon energy, and optical properties reveal a well-defined optimum kinetic energy of 90 eV to deposit ta-C films having the largest sp3 fraction and the widest optical (Tauc) energy gap (equivalent to minimum near-gap optical absorption). Tapping-mode atomic force microscope measurements show that films deposited at near-optimum kinetic energy are extremely smooth, with rms roughness of only ~ 1 Å over distances of several hundred nm, and are relatively free of particulates.
Collapse
|
44
|
Anders S, Anders A, Ager JW, Wang Z, Pharr GM, Tsui TY, Brown IG, Bhatia CS. Mechanical Properties of Amorphous Hard Carbon Films Prepared by Cathodic ARC Deposition. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-383-453] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTCathodic arc deposition combined with macroparticle filtering of the plasma is an efficient and versatile method for the deposition of amorphous hard carbon films of high quality. The film properties can be tailored over a broad range by varying the energy of the carbon ions incident upon the substrate and upon the growing film by applying a pulsed bias technique. By varying the bias voltage during the deposition process specific properties of the interface, bulk film and top surface layer can be obtained. We report on nanoindentation and transmission electron microscopy studies as well as stress measurements of cathodic-arc amorphous hard carbon films deposited with varied bias voltage. The investigations were performed on multilayers consisting of alternating hard and soft amorphous carbon.
Collapse
|
45
|
Shi X, Tay BK, Flynn DI, Sun Z. Tribological Properties of Tetrahedral Carbon Films Deposited by Filtered Cathodic Vacuum Arc Technique. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-436-293] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractTa-C films have been deposited using FCVA technique. The hardness and Young's modulus of the films on both silicon and sapphire substrates are determined by an ultra low load depth sensing nanoindenter to examine their dependence on the carbon ion energy. An optimum ion energy around 80 to 90 eV has been found, which coincides with the energy at which the sp3 content and film density reach maximum values. At this ion energy, the hardness, modulus and critical load of a 60 nm film on sapphire exhibit maximum values of 60 GPa, 580 GPa and 7 mN, respectively, whilst the frictional coefficient shows a minimum of 0.16.
Collapse
|
46
|
Chhowalla M, Chen CW, Kleinsorge B, Robertson J, Amaratunga GAJ, Milne WI. Properties of Tetrahedral Amorphous Carbon Deposited by A Filtered Cathodic Vacuum ARC. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-423-299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe properties of a highly sp3 bonded form of amorphous carbon denoted ta-C deposited from a filtered cathodic vacuum arc (FCVA) are described as a function of ion energy and deposition temperature. The sp3 fraction depends strongly on ion energy and reaches 85% at an ion energy of 100 eV. Other properties such as density and band gap vary in a similar fashion, with the optical gap reaching a maximum of 2.3 eV. These films are very smooth with area roughness of order 1 nm. The sp3 fraction falls suddenly to almost zero for deposition above about 200°C.
Collapse
|
47
|
Robertson J, Milne WI. Properties of Diamond-Like Carbon for Thin Film Microcathodes for Field Emission Displays. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-424-381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractDiamond-like carbon is a strong candidate for field emission microcathodes for field emission displays because of its low electron affinity and chemical inertness. The field emission properties of various types of diamond-like carbon such as a-C:H and ta-C are reviewed in the framework of a bonding model of their affinity.
Collapse
|
48
|
Gilkes KWR, Prawer S, Robertson J, Sands HS. Quantitative Studies of Tetrahedral Bonding in Amorphous Carbon Films Using Ultraviolet Raman Spectroscopy. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-498-49] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe bonding in a series of unhydrogenated amorphous carbon films has been analysed quantitatively using Raman spectroscopy with ultraviolet excitation. The Raman spectra exhibit two broad Raman peaks at 1650 cm−1 and 1100 cm−1, due to sp2 and sp3 vibrational modes respectively. The former is a resonance feature associated with a large proportion of paired sp2 sites, while the latter is a weighted vibrational density-of-states for the distorted random network of sp3 sites. The position and relative intensity of the two peaks are shown to be strongly correlated with the percentage of sp3 sites in the films, providing a reliable measure of sp3 bonding which is both quantitative and non-destructive.
Collapse
|
49
|
Abstract
AbstractWe review for diamond-like carbon the various deposition methods, the deposition mechanisms of subplantation and ion-assisted addition, the characterisation methods such as Raman and electron energy loss spectroscopy, its mechanical properties and some applications as a coating material.
Collapse
|
50
|
Milne WI, Robertson J, Satyanarayana BS, Hart A, Kleinsorge B. Field Emission From Tetrahedrally Bonded Amorphous Carbon as a Function of Surface Treatment and Contact Material. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-498-209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTIn order to test whether field emission from tetrahedrally bonded amorphous (ta-C) is affected by the back contact material we have carried out a series of emission experiments on Filtered Cathodic Vacuum Arc (FCVA) produced ta-C films. The measurements were made on identical films of approximately 25 nm thickness which have been grown simultaneously on various substrates of different work function. For these experiments the substrates used were p-type c-Si, n-type c-Si, SnO2, tungsten, gold, lead, aluminium, molybdenum, chromium and titanium. Threshold fields for emission were generally in the range of 5–15 V/micron and showed no direct dependence on back contact material work function. Films grown on Ti and W however had much higher threshold fields in the range 30–35 V/micron and this is thought to be associated with the native oxide which was present between the back contact and the ta-C film. As grown ta-C is also known to have a 1–2 nm thick sp2 rich layer on its surface and this layer may also have some effect on field emission. The layer was etched in either an O2 or H2 plasma and both etched surfaces led to improved emission efficiency.
Collapse
|