1
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Kang S, Wang D, Kübel C, Mu X. Importance of TEM sample thickness for measuring strain fields. Ultramicroscopy 2024; 255:113844. [PMID: 37708815 DOI: 10.1016/j.ultramic.2023.113844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 07/26/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023]
Abstract
Transmission electron microscopy (TEM) has emerged as a valuable tool for assessing and mapping strain fields within materials. By directly analyzing local atomic spacing variations, TEM enables the precise measurement of local strain with high spatial resolution. However, it is standard practice to use thin specimens in TEM analysis to ensure electron transparency and minimize issues such as projection artifacts and contributions from multiple scattering. This raises an important question regarding the extent of structural modification, such as strain relaxation, induced in thin samples due to the increased surface-to-volume ratio and the thinning process. In this study, we conducted a systematic investigation to quantify the influence of TEM sample thickness on the residual strain field using deformed Fe-based and Zr-based metallic glasses as model systems. The samples were gradually thinned from 300 nm to 70 nm, and the same area was examined using 4D-STEM with identical imaging settings. Our results demonstrate that thinning the sample affects the atomic configuration at both the short-range (SR) and medium-range (MR) scales. Consequently, when the sample is thinned too much, it no longer preserves the native deformation structure. These findings highlight the critical importance of maintaining sufficient TEM sample thickness for obtaining meaningful and accurate strain measurements.
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Affiliation(s)
- Sangjun Kang
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany; Joint Research Laboratory Nanomaterials, Technical University of Darmstadt (TUDa), Darmstadt 64287, Germany.
| | - Di Wang
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany; Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany
| | - Christian Kübel
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany; Joint Research Laboratory Nanomaterials, Technical University of Darmstadt (TUDa), Darmstadt 64287, Germany; Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany.
| | - Xiaoke Mu
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen 76344, Germany.
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2
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Sun Y, Yao Q, Xing W, Jiang H, Li Y, Xiong W, Zhu W, Zheng Y. Residual Strain Evolution Induced by Crystallization Kinetics During Anti-Solvent Spin Coating in Organic-Inorganic Hybrid Perovskite. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2205986. [PMID: 37096861 DOI: 10.1002/advs.202205986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/03/2023] [Indexed: 05/03/2023]
Abstract
Organic-inorganic hybrid perovskite (OIHP) polycrystalline thin films are attractive due to their outstanding photoelectronic properties. The anti-solvent spin coating method is the most widely used to synthesize these thin films, and the residual strain is inevitably originates and evolves during the process. However, this residual strain evolution induced by crystallization kinetics is still poorly understood. In this work, the in situ and ex situ synchrotron grazing-incidence wide-angle X-ray scattering (GIWAXS) are utilized to characterize the evolution and distribution of the residual strain in the OIHP polycrystalline thin film during the anti-solvent spin coating process. A mechanical model is established and the mechanism of the crystallization kinetics-induced residual strain evolution process is discussed. This work reveals a comprehensive understanding of the residual strain evolution during the anti-solvent spin coating process in the OIHP polycrystalline thin films and provides important guidelines for the residual strain-related strain engineering, morphology control, and performance enhancement.
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Affiliation(s)
- Y Sun
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - Q Yao
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - W Xing
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - H Jiang
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - Y Li
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - W Xiong
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - W Zhu
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
| | - Y Zheng
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou, 510275, China
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3
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Durinck J, Hamade S, Grilhé J, Colin J. Pressure and folding effects on the buckling of a freestanding compressed thin film. Phys Rev E 2023; 107:035003. [PMID: 37073005 DOI: 10.1103/physreve.107.035003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/02/2023] [Indexed: 04/20/2023]
Abstract
The combined effects of compressive stress, applied pressure, and edge folding of a freestanding thin film have been theoretically investigated on the buckle morphologies of the structure. In the framework of the Föppl-von Kármán theory of thin plates, the different buckle profiles have been analytically determined, and two buckling regimes have been identified for the film: one regime where the transition from upward to downward buckling is continuous, and one that is discontinuous (snap-through). The critical pressures characterizing the different regimes have then been determined, and an hysteresis cycle has been identified through the study of buckling versus pressure. The case in which the thin film is deposited on a substrate has also been discussed.
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Affiliation(s)
- J Durinck
- Institut Pprime, UPR 3346 CNRS, Université de Poitiers-ENSMA-CNRS, 86073 Poitiers cedex, France
| | - S Hamade
- Polytech'Lab, UPR UCA 7498, Université Nice Sophia Antipolis, 06903 Sophia Antipolis cedex, France
| | - J Grilhé
- Institut Pprime, UPR 3346 CNRS, Université de Poitiers-ENSMA-CNRS, 86073 Poitiers cedex, France
| | - J Colin
- Institut Pprime, UPR 3346 CNRS, Université de Poitiers-ENSMA-CNRS, 86073 Poitiers cedex, France
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4
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Soares CO, Buvat G, Hernández YG, Garbarino S, Duca M, Ruediger A, Denuault G, Tavares AC, Guay D. Au(001) Thin Films: Impact of Structure and Mosaicity on the Oxygen Reduction Reaction in Alkaline Medium. ACS Catal 2022. [DOI: 10.1021/acscatal.1c04407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cybelle Oliveira Soares
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Gaëtan Buvat
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
- Institut d’Electronique, de Microélectronique et de Nanotechnologies, Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, UMR 8520─IEMN, Lille F-59000, France
| | - Yoandris González Hernández
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Sébastien Garbarino
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
- PRIMA Québec, 505 Boulevard Maisonneuve Ouest, Montréal, Québec H3A 3C2, Canada
| | - Matteo Duca
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
- Département de chimie, Complexe des sciences, CQMF, Université de Montréal─Campus MIL, Bureau B-4039, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V 0B3, Canada
| | - Andreas Ruediger
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Guy Denuault
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Ana C. Tavares
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Daniel Guay
- Institut National de la Recherche Scientifique─Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
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5
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Nakamura N, Kashiuchi K, Ogi H. Multi-mode resistive spectroscopy for precisely controlling morphology of extremely narrow gap palladium nanocluster array. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:063901. [PMID: 34243545 DOI: 10.1063/5.0049536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
During the deposition of a metallic material on a substrate, a nanocluster-array structure with an extremely narrow gap is formed transiently at the transition between isolated clusters and the continuous film. It is known that the nanocluster array shows a unique electrical property different from that of isolated clusters and the continuous film. The electrical property of the nanocluster array changes significantly depending on its morphology, and precise control of the deposition time is indispensable to obtain a desired electrical property. However, the detection of the transition is not straightforward. To overcome this problem, we develop the multi-mode resistive spectroscopy. It evaluates the morphological change during deposition using resonant vibrations of a piezoelectric material and enables the fabrication of nanocluster arrays with a slightly different morphology. Palladium nanocluster arrays with different morphologies are fabricated using this method, and the availability of the multi-mode resistive spectroscopy is demonstrated by evaluating their electrical response to hydrogen gas.
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Affiliation(s)
- N Nakamura
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - K Kashiuchi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - H Ogi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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6
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Nakamura N, Sakamoto Y, Ogi H. Spontaneous nucleation on flat surface by depletion force in colloidal suspension. Sci Rep 2021; 11:8929. [PMID: 33903604 PMCID: PMC8076313 DOI: 10.1038/s41598-021-87626-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/31/2021] [Indexed: 11/10/2022] Open
Abstract
Nucleation by sedimentation of colloidal particles on a flat surface is experimentally observed, and effect of attractive depletion force generated by polymers on nucleation is investigated. Sedimentation forms polycrystalline colloidal crystal on a flat surface, and above the threshold polymer concentration, ratio of the spontaneous nucleation increases, resulting in a decrease in the grain size, whereas dependence of the contact angle on the polymer concentration was not observed. We show that the interaction between particles and the flat surface mainly affects the spontaneous nucleation, not the interaction between the particles, and it is demonstrated that the nucleation process can be numerically reproduced using the rate equations.
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Affiliation(s)
- Nobutomo Nakamura
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan.
| | - Yuto Sakamoto
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Hirotsugu Ogi
- Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
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7
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Zou P, Sui Y, Zhan H, Wang C, Xin HL, Cheng HM, Kang F, Yang C. Polymorph Evolution Mechanisms and Regulation Strategies of Lithium Metal Anode under Multiphysical Fields. Chem Rev 2021; 121:5986-6056. [PMID: 33861070 DOI: 10.1021/acs.chemrev.0c01100] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lithium (Li) metal, a typical alkaline metal, has been hailed as the "holy grail" anode material for next generation batteries owing to its high theoretical capacity and low redox reaction potential. However, the uncontrolled Li plating/stripping issue of Li metal anodes, associated with polymorphous Li formation, "dead Li" accumulation, poor Coulombic efficiency, inferior cyclic stability, and hazardous safety risks (such as explosion), remains as one major roadblock for their practical applications. In principle, polymorphous Li deposits on Li metal anodes includes smooth Li (film-like Li) and a group of irregularly patterned Li (e.g., whisker-like Li (Li whiskers), moss-like Li (Li mosses), tree-like Li (Li dendrites), and their combinations). The nucleation and growth of these Li polymorphs are dominantly dependent on multiphysical fields, involving the ionic concentration field, electric field, stress field, and temperature field, etc. This review provides a clear picture and in-depth discussion on the classification and initiation/growth mechanisms of polymorphous Li from the new perspective of multiphysical fields, particularly for irregular Li patterns. Specifically, we discuss the impact of multiphysical fields' distribution and intensity on Li plating behavior as well as their connection with the electrochemical and metallurgical properties of Li metal and some other factors (e.g., electrolyte composition, solid electrolyte interphase (SEI) layer, and initial nuclei states). Accordingly, the studies on the progress for delaying/suppressing/redirecting irregular Li evolution to enhance the stability and safety performance of Li metal batteries are reviewed, which are also categorized based on the multiphysical fields. Finally, an overview of the existing challenges and the future development directions of metal anodes are summarized and prospected.
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Affiliation(s)
- Peichao Zou
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Yiming Sui
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Houchao Zhan
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Chunyang Wang
- Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Huolin L Xin
- Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Hui-Ming Cheng
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,Shenyang National Laboratory for Materials Sciences, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Feiyu Kang
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Cheng Yang
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
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8
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Yu Y, Jung GS, Liu C, Lin YC, Rouleau CM, Yoon M, Eres G, Duscher G, Xiao K, Irle S, Puretzky AA, Geohegan DB. Strain-Induced Growth of Twisted Bilayers during the Coalescence of Monolayer MoS 2 Crystals. ACS NANO 2021; 15:4504-4517. [PMID: 33651582 DOI: 10.1021/acsnano.0c08516] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tailoring the grain boundaries (GBs) and twist angles between two-dimensional (2D) crystals are two crucial synthetic challenges to deterministically enable envisioned applications such as moiré excitons, emerging magnetism, or single-photon emission. Here, we reveal how twisted 2D bilayers can be synthesized from the collision and coalescence of two growing monolayer MoS2 crystals during chemical vapor deposition. The twisted bilayer (TB) moiré angles are found to preserve the misorientation angle (θ) of the colliding crystals. The shapes of the TB regions are rationalized by a kink propagation model that predicts the GB formed by the coalescing crystals. Optical spectroscopy measurements reveal a θ-dependent long-range strain in crystals with stitched grain boundaries and a sharp (θ > 20°) threshold for the appearance of TBs, which relieves this strain. Reactive molecular dynamics simulations explain this strain from the continued growth of the crystals during coalescence due to the insertion of atoms at unsaturated defects along the GB, a process that self-terminates when the defects become saturated. The simulations also reproduce atomic-resolution electron microscopy observations of faceting along the GB, which is shown to arise from the growth-induced long-range strain. These facets align with the axes of the colliding crystals to provide favorable nucleation sites for second-layer growth of a TB with twist angles that preserve the misorientation angle θ. This interplay between strain generation and aligned nucleation provides a synthetic pathway for the growth of TBs with deterministic angles.
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Affiliation(s)
- Yiling Yu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gang Seob Jung
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Chenze Liu
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Yu-Chuan Lin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Christopher M Rouleau
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Mina Yoon
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gyula Eres
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gerd Duscher
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Stephan Irle
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - David B Geohegan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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9
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Cancellieri C, Ariosa D, Druzhinin AV, Unutulmazsoy Y, Neels A, Jeurgens LP. Strain depth profiles in thin films extracted from in-plane X-ray diffraction. J Appl Crystallogr 2021. [DOI: 10.1107/s1600576720014843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Thin films generally contain depth-dependent residual stress gradients, which influence their functional properties and stability in harsh environments. An understanding of these stress gradients and their influence is crucial for many applications. Standard methods for thin-film stress determination only provide average strain values, thus disregarding possible variation in strain/stress across the film thickness. This work introduces a new method to derive depth-dependent strain profiles in thin films with thicknesses in the submicrometre range by laboratory-based in-plane grazing X-ray diffraction, as applied to magnetron-sputtering-grown polycrystalline Cu thin films with different thicknesses. By performing in-plane grazing diffraction analysis at different incidence angles, the in-plane lattice constant depth profile of the thin film can be resolved through a dedicated robust data processing procedure. Owing to the underlying intrinsic difficulties related to the inverse Laplace transform of discrete experimental data sets, four complementary procedures are presented to reliably extract the strain depth profile of the films from the diffraction data. Surprisingly, the strain depth profile is not monotonic and possesses a complex shape: highly compressive close to the substrate interface, more tensile within the film and relaxed close to the film surface. The same strain profile is obtained by the four different data evaluation methods, confirming the validity of the derived depth-dependent strain profiles as a function of the film thickness. Comparison of the obtained results with the average in-plane stresses independently derived by the standard stress analysis method in the out-of-plane diffraction geometry validates the solidity of the proposed method.
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10
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Colin J, Jamnig A, Furgeaud C, Michel A, Pliatsikas N, Sarakinos K, Abadias G. In Situ and Real-Time Nanoscale Monitoring of Ultra-Thin Metal Film Growth Using Optical and Electrical Diagnostic Tools. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E2225. [PMID: 33182409 PMCID: PMC7697846 DOI: 10.3390/nano10112225] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 01/08/2023]
Abstract
Continued downscaling of functional layers for key enabling devices has prompted the development of characterization tools to probe and dynamically control thin film formation stages and ensure the desired film morphology and functionalities in terms of, e.g., layer surface smoothness or electrical properties. In this work, we review the combined use of in situ and real-time optical (wafer curvature, spectroscopic ellipsometry) and electrical probes for gaining insights into the early growth stages of magnetron-sputter-deposited films. Data are reported for a large variety of metals characterized by different atomic mobilities and interface reactivities. For fcc noble-metal films (Ag, Cu, Pd) exhibiting a pronounced three-dimensional growth on weakly-interacting substrates (SiO2, amorphous carbon (a-C)), wafer curvature, spectroscopic ellipsometry, and resistivity techniques are shown to be complementary in studying the morphological evolution of discontinuous layers, and determining the percolation threshold and the onset of continuous film formation. The influence of growth kinetics (in terms of intrinsic atomic mobility, substrate temperature, deposition rate, deposition flux temporal profile) and the effect of deposited energy (through changes in working pressure or bias voltage) on the various morphological transition thicknesses is critically examined. For bcc transition metals, like Fe and Mo deposited on a-Si, in situ and real-time growth monitoring data exhibit transient features at a critical layer thickness of ~2 nm, which is a fingerprint of an interface-mediated crystalline-to-amorphous phase transition, while such behavior is not observed for Ta films that crystallize into their metastable tetragonal β-Ta allotropic phase. The potential of optical and electrical diagnostic tools is also explored to reveal complex interfacial reactions and their effect on growth of Pd films on a-Si or a-Ge interlayers. For all case studies presented in the article, in situ data are complemented with and benchmarked against ex situ structural and morphological analyses.
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Affiliation(s)
- Jonathan Colin
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Andreas Jamnig
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Clarisse Furgeaud
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Anny Michel
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Nikolaos Pliatsikas
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Kostas Sarakinos
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Gregory Abadias
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
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11
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Influence of the Thickness of a Nanolayer Composite Coating on Values of Residual Stress and the Nature of Coating Wear. COATINGS 2020. [DOI: 10.3390/coatings10010063] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The article discusses the influence of the thickness of the wear-resistant layer of the Zr-ZrN-(Zr,Al,Si)N nanolayer composite coating on the values of residual stress and the nature of coating wear. The study focused on coatings with wear-resistant layer thicknesses of 2.0, 4.3, 5.9, and 8.5 µm, deposited using filtered cathodic vacuum arc deposition (FCVAD) technology. The X-ray diffraction (XRD) method based on the anisotropy of the elasticity modulus was used to find the values of the residual stress. The nature of the formation of interlayer delamination under the influence of residual compressive stress was studied using a scanning electron microscope (SEM). When the wear-resistant layers had a thickness of 2.0–5.9 μm, tensile stress formed, which decreased with an increase in the thickness of the coating. When the thickness of a wear-resistant layer was 8.5 μm, compressive stress formed. Under the action of compressive stress, periodic interlayer delamination formed, with a pitch of about 10 binary nanolayers. A mathematical model is proposed to describe the nature of the formation of interlayer delamination under the influence of compressive residual stress, including in the presence of a microdroplet embedded in the coating structure.
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12
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Growth mechanism identification of sputtered single crystalline bismuth nanowire. APPLIED NANOSCIENCE 2019. [DOI: 10.1007/s13204-019-01026-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Effect of Thickness of Molybdenum Nano-Interlayer on Cohesion between Molybdenum/Titanium Multilayer Film and Silicon Substrate. NANOMATERIALS 2019; 9:nano9040616. [PMID: 31014008 PMCID: PMC6523496 DOI: 10.3390/nano9040616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/08/2019] [Accepted: 04/11/2019] [Indexed: 11/16/2022]
Abstract
Titanium (Ti) film has been used as a hydrogen storage material. The effect of the thickness of a molybdenum (Mo) nano-interlayer on the cohesive strength between a Mo/Ti multilayer film and a single crystal silicon (Si) substrate was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nano-indenter. Four groups of Si/Mo/Ti multilayer films with different thicknesses of Mo and Ti films were fabricated. The XRD results showed that the introduction of the Mo layer suppressed the chemical reaction between the Ti film and Si substrate. The nano-indenter scratch results demonstrated that the cohesion between the Mo/Ti film and Si substrate decreased significantly with increasing Mo interlayer thickness. The XRD stress analysis indicated that the residual stress in the Si/Mo/Ti film was in-plane tensile stress which might be due to the lattice expansion at a high film growth temperature of 700 °C and the discrepancy of the thermal expansion coefficient between the Ti film and Si substrate. The tensile stress in the Si/Mo/Ti film decreased with increasing Mo interlayer thickness. During the cooling of the Si substrate, a greater decrease in tensile stress occurred for the thicker Mo interlayer sample, which became the driving force for reducing the cohesion between the Mo/Ti film and Si substrate. The results confirmed that the design of the Mo interlayer played an important role in the quality of the Ti film grown on Si substrate.
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14
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Sun CZ, Hong RD, Chen XP, Cai JF, Wu ZY. Ultraviolet optical properties and structural characteristics of radio frequency-deposited HfO2 thin films. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1806140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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15
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The Effect of Interfacial Ge and RF-Bias on the Microstructure and Stress Evolution upon Annealing of Ag/AlN Multilayers. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8122403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study addresses the structural stability and mass outflow of Ag 10 nm/Ge 1 nm/AlN 10 nm nanomultilayers (NMLs) during thermal treatments in different atmospheres (Ar and air). The nanomultilayers were obtained by magnetron sputtering under different deposition conditions (with and without the RF (Radio-Frequency)-bias application). The microstructure of the as-deposited and thermally treated NMLs were analyzed by XRD and SEM techniques, deriving morphology, microstructure and internal stress. Bias application during the deposition is found to create highly disordered interfaces and to have a very strong influence on the morphology and structural evolution with temperature of the nano-multilayers. Complete multilayer degradation is observed for the bias sample when annealed in Ar at 700 ∘C, while the periodic multilayer structure is preserved for the non-bias samples. Structural and morphological changes are observed starting from 400 ∘C, accompanied with Ag surface migration. The highest Ag amount on the surface is detected in air atmosphere for bias and non-bias samples annealed at temperatures as high as 700 ∘C. The presence of Ge is found to strongly hinder the Ag surface migration. Ag outflow is measured to take place only through the network of surface cracks in the AlN barrier formed upon heating. The crack formation and Ag migration are discussed together with the stress relaxation. The present study demonstrates the feasibility to tailor the stress state of as-deposited NML structures and observe different structural evolution depending on the initial conditions. This paves the way for advanced experimental strategies to tailor directional mass outflow in nanoconfined filler systems for advanced nano-joining applications.
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16
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Pateras A, Park J, Ahn Y, Tilka JA, Holt MV, Reichl C, Wegscheider W, Baart TA, Dehollain JP, Mukhopadhyay U, Vandersypen LMK, Evans PG. Mesoscopic Elastic Distortions in GaAs Quantum Dot Heterostructures. NANO LETTERS 2018; 18:2780-2786. [PMID: 29664645 DOI: 10.1021/acs.nanolett.7b04603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum devices formed in high-electron-mobility semiconductor heterostructures provide a route through which quantum mechanical effects can be exploited on length scales accessible to lithography and integrated electronics. The electrostatic definition of quantum dots in semiconductor heterostructure devices intrinsically involves the lithographic fabrication of intricate patterns of metallic electrodes. The formation of metal/semiconductor interfaces, growth processes associated with polycrystalline metallic layers, and differential thermal expansion produce elastic distortion in the active areas of quantum devices. Understanding and controlling these distortions present a significant challenge in quantum device development. We report synchrotron X-ray nanodiffraction measurements combined with dynamical X-ray diffraction modeling that reveal lattice tilts with a depth-averaged value up to 0.04° and strain on the order of 10-4 in the two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure. Elastic distortions in GaAs/AlGaAs heterostructures modify the potential energy landscape in the 2DEG due to the generation of a deformation potential and an electric field through the piezoelectric effect. The stress induced by metal electrodes directly impacts the ability to control the positions of the potential minima where quantum dots form and the coupling between neighboring quantum dots.
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Affiliation(s)
- Anastasios Pateras
- Department of Materials Science & Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Joonkyu Park
- Department of Materials Science & Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Youngjun Ahn
- Department of Materials Science & Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jack A Tilka
- Department of Materials Science & Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Martin V Holt
- Center for Nanoscale Materials , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Christian Reichl
- Laboratory for Solid State Physics , ETH Zürich , Zürich CH-8093 , Switzerland
| | - Werner Wegscheider
- Laboratory for Solid State Physics , ETH Zürich , Zürich CH-8093 , Switzerland
| | - Timothy A Baart
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , PO Box 5046, 2600 GA Delft , The Netherlands
| | - Juan Pablo Dehollain
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , PO Box 5046, 2600 GA Delft , The Netherlands
| | - Uditendu Mukhopadhyay
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , PO Box 5046, 2600 GA Delft , The Netherlands
| | - Lieven M K Vandersypen
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , PO Box 5046, 2600 GA Delft , The Netherlands
| | - Paul G Evans
- Department of Materials Science & Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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17
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Sarkar A, Ashraf T, Grafeneder W, Koch R. Interface structure and composition of MoO 3/GaAs(0 0 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:155001. [PMID: 29498362 DOI: 10.1088/1361-648x/aab391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We studied growth, structure, stress, oxidation state as well as surface and interface structure and composition of thermally-evaporated thin MoO3 films on the technologically important III/V-semiconductor substrate GaAs(0 0 1). The MoO3 films grow with Mo in the 6+ oxidation state. The electrical resistance is tunable by the oxygen partial pressure during deposition from transparent insulating to semi-transparant halfmetallic. In the investigated growth temperature range (room temperature to 200 °C) no diffraction spots are detected by x-ray diffraction. However, high resolution transmission electron microscopy reveals the formation of MoO3 nanocrystal grains with diameters of 5-8 nm. At the interface a ≈3 nm-thick intermediate layer has formed, where the single-crystal lattice of GaAs gradually transforms to the nanocrystalline MoO3 structure. This interpretation is corroborated by our in situ and real-time stress measurements evidencing a two-stage growth process as well as by elemental interface analysis revealing coexistance of Ga, As, Mo, and oxygen in a intermediate layer of 3-4 nm.
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18
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Gebhard M, Mai L, Banko L, Mitschker F, Hoppe C, Jaritz M, Kirchheim D, Zekorn C, de Los Arcos T, Grochla D, Dahlmann R, Grundmeier G, Awakowicz P, Ludwig A, Devi A. PEALD of SiO 2 and Al 2O 3 Thin Films on Polypropylene: Investigations of the Film Growth at the Interface, Stress, and Gas Barrier Properties of Dyads. ACS APPLIED MATERIALS & INTERFACES 2018; 10:7422-7434. [PMID: 29338170 DOI: 10.1021/acsami.7b14916] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A study on the plasma-enhanced atomic layer deposition of amorphous inorganic oxides SiO2 and Al2O3 on polypropylene (PP) was carried out with respect to growth taking place at the interface of the polymer substrate and the thin film employing in situ quartz-crystal microbalance (QCM) experiments. A model layer of spin-coated PP (scPP) was deposited on QCM crystals prior to depositions to allow a transfer of findings from QCM studies to industrially applied PP foil. The influence of precursor choice (trimethylaluminum (TMA) vs [3-(dimethylamino)propyl]-dimethyl aluminum (DMAD)) and of plasma pretreatment on the monitored QCM response was investigated. Furthermore, dyads of SiO2/Al2O3, using different Al precursors for the Al2O3 thin-film deposition, were investigated regarding their barrier performance. Although the growth of SiO2 and Al2O3 from TMA on scPP is significantly hindered if no oxygen plasma pretreatment is applied to the scPP prior to depositions, the DMAD process was found to yield comparable Al2O3 growth directly on scPP similar to that found on a bare QCM crystal. From this, the interface formed between the Al2O3 and the PP substrate is suggested to be different for the two precursors TMA and DMAD due to different growth modes. Furthermore, the residual stress of the thin films influences the barrier properties of SiO2/Al2O3 dyads. Dyads composed of 5 nm Al2O3 (DMAD) + 5 nm SiO2 exhibit an oxygen transmission rate (OTR) of 57.4 cm3 m-2 day-1, which correlates with a barrier improvement factor of 24 against 5 when Al2O3 from TMA is applied.
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Affiliation(s)
| | | | | | | | - Christian Hoppe
- Technical and Macromolecular Chemistry, University of Paderborn , 33098 Paderborn, Germany
| | - Montgomery Jaritz
- Institute for Plastics Processing (IKV), RWTH Aachen University , 52074 Aachen, Germany
| | - Dennis Kirchheim
- Institute for Plastics Processing (IKV), RWTH Aachen University , 52074 Aachen, Germany
| | - Christoph Zekorn
- Institute for Plastics Processing (IKV), RWTH Aachen University , 52074 Aachen, Germany
| | - Teresa de Los Arcos
- Technical and Macromolecular Chemistry, University of Paderborn , 33098 Paderborn, Germany
| | | | - Rainer Dahlmann
- Institute for Plastics Processing (IKV), RWTH Aachen University , 52074 Aachen, Germany
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, University of Paderborn , 33098 Paderborn, Germany
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19
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Vasco E, Polop C. Intrinsic Compressive Stress in Polycrystalline Films is Localized at Edges of the Grain Boundaries. PHYSICAL REVIEW LETTERS 2017; 119:256102. [PMID: 29303313 DOI: 10.1103/physrevlett.119.256102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Indexed: 06/07/2023]
Abstract
The intrinsic compression that arises in polycrystalline thin films under high atomic mobility conditions has been attributed to the insertion or trapping of adatoms inside grain boundaries. This compression is a consequence of the stress field resulting from imperfections in the solid and causes the thermomechanical fatigue that is estimated to be responsible for 90% of mechanical failures in current devices. We directly measure the local distribution of residual intrinsic stress in polycrystalline thin films on nanometer scales, using a pioneering method based on atomic force microscopy. Our results demonstrate that, at odds with expectations, compression is not generated inside grain boundaries but at the edges of gaps where the boundaries intercept the surface. We describe a model wherein this compressive stress is caused by Mullins-type surface diffusion towards the boundaries, generating a kinetic surface profile different from the mechanical equilibrium profile by the Laplace-Young equation. Where the curvatures of both profiles differ, an intrinsic stress is generated in the form of Laplace pressure. The Srolovitz-type surface diffusion that results from the stress counters the Mullins-type diffusion and stabilizes the kinetic surface profile, giving rise to a steady compression regime. The proposed mechanism of competition between surface diffusions would explain the flux and time dependency of compressive stress in polycrystalline thin films.
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Affiliation(s)
- Enrique Vasco
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Celia Polop
- Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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20
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Polop C, Vasco E, Perrino AP, Garcia R. Mapping stress in polycrystals with sub-10 nm spatial resolution. NANOSCALE 2017; 9:13938-13946. [PMID: 28686260 DOI: 10.1039/c7nr00800g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
From aircraft to electronic devices, and even in Formula One cars, stress is the main cause of degraded material performance and mechanical failure in applications incorporating thin films and coatings. Over the last two decades, the scientific community has searched for the mechanisms responsible for stress generation in films, with no consensus in sight. The main difficulty is that most current models of stress generation, while atomistic in nature, are based on macroscopic measurements. Here, we demonstrate a novel method for mapping the stress at the surface of polycrystals with sub-10 nm spatial resolution. This method consists of transforming elastic modulus maps measured by atomic force microscopy techniques into stress maps via the local stress-stiffening effect. The validity of this approach is supported by finite element modeling simulations. Our study reveals a strongly heterogeneous distribution of intrinsic stress in polycrystalline Au films, with gradients as high as 100 MPa nm-1 near the grain boundaries. Consequently, our study discloses the limited capacity of macroscopic stress assessments and standard tests to discriminate among models, and the great potential of nanometer-scale stress mapping.
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Affiliation(s)
- C Polop
- Departamento de Física de la Materia Condensada and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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21
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Banu N, Singh S, Satpati B, Roy A, Basu S, Chakraborty P, Movva HCP, Lauter V, Dev BN. Evidence of Formation of Superdense Nonmagnetic Cobalt. Sci Rep 2017; 7:41856. [PMID: 28157186 PMCID: PMC5291096 DOI: 10.1038/srep41856] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 12/29/2016] [Indexed: 11/28/2022] Open
Abstract
Because of the presence of 3d transition metals in the Earth’s core, magnetism of these materials in their dense phases has been a topic of great interest. Theory predicts a dense face-centred-cubic phase of cobalt, which would be nonmagnetic. However, this dense nonmagnetic cobalt has not yet been observed. Recent investigations in thin film polycrystalline materials have shown the formation of compressive stress, which can increase the density of materials. We have discovered the existence of ultrathin superdense nonmagnetic cobalt layers in a polycrystalline cobalt thin film. The densities of these layers are about 1.2–1.4 times the normal density of Co. This has been revealed by X-ray reflectometry experiments, and corroborated by polarized neutron reflectometry (PNR) experiments. Transmission electron microscopy provides further evidence. The magnetic depth profile, obtained by PNR, shows that the superdense Co layers near the top of the film and at the film-substrate interface are nonmagnetic. The major part of the Co film has the usual density and magnetic moment. These results indicate the possibility of existence of nonmagnetic Co in the earth’s core under high pressure.
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Affiliation(s)
- Nasrin Banu
- Department of Materials Science, Indian Association for the Cultivation of Science, 2A &2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Surendra Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - B Satpati
- Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - A Roy
- Microelectronic Research Center, The University of Texas at Austin, 10100 Burnet Road, Bldg 160, MER 1.606J, Austin, Texas 78758, USA
| | - S Basu
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - P Chakraborty
- Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - Hema C P Movva
- Microelectronic Research Center, The University of Texas at Austin, 10100 Burnet Road, Bldg 160, MER 1.606J, Austin, Texas 78758, USA
| | - V Lauter
- Quantum Condensed Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831-6475, USA
| | - B N Dev
- Department of Materials Science, Indian Association for the Cultivation of Science, 2A &2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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22
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Zhao Z, Du L, Tao Y, Li Q, Luo L. Enhancing the adhesion strength of micro electroforming layer by ultrasonic agitation method and the application. ULTRASONICS SONOCHEMISTRY 2016; 33:10-17. [PMID: 27245951 DOI: 10.1016/j.ultsonch.2016.04.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 05/21/2023]
Abstract
Micro electroforming is widely used for fabricating micro metal devices in Micro Electro Mechanism System (MEMS). However, there is the problem of poor adhesion strength between micro electroforming layer and substrate. This dramatically influences the dimensional accuracy of the device. To solve this problem, ultrasonic agitation method is applied during the micro electroforming process. To explore the effect of the ultrasonic agitation on the adhesion strength, micro electroforming experiments were carried out under different ultrasonic power (0W, 100W, 150W, 200W, 250W) and different ultrasonic frequencies (0kHz, 40kHz, 80kHz, 120kHz, 200kHz). The effects of the ultrasonic power and the ultrasonic frequency on the micro electroforming process were investigated by polarization method and alternating current (a.c.) impedance method. The adhesion strength between the electroforming layer and the substrate was measured by scratch test. The compressive stress of the electroforming layer was measured by X-ray Diffraction (XRD) method. The crystallite size of the electroforming layer was measured by Transmission Electron Microscopy (TEM) method. The internal contact surface area of the electroforming layer was measured by cyclic voltammetry (CV) method. The experimental results indicate that the ultrasonic agitation can decrease the polarization overpotential and increase the charge transfer process. Generally, the internal contact surface area is increased and the compressive stress is reduced. And then the adhesion strength is enhanced. Due to the different depolarization effects of the ultrasonic power and the ultrasonic frequency, the effects on strengthening the adhesion strength are different. When the ultrasonic agitation is 200W and 40kHz, the effect on strengthening the adhesion strength is the best. In order to prove the effect which the ultrasonic agitation can improve the adhesion strength of the micro devices, micro pillar arrays were fabricated under ultrasonic agitation (200W, 40kHz). The experimental results show that the residual rate of the micro pillar arrays is increased about 17% by ultrasonic agitation method. This work contributes to fabricating the electroforming layer with large adhesion strength.
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Affiliation(s)
- Zhong Zhao
- Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Liqun Du
- Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, People's Republic of China; Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China.
| | - Yousheng Tao
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Qingfeng Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Lei Luo
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China
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23
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Sheth J, Chen D, Kim JJ, Bowman WJ, Crozier PA, Tuller HL, Misture ST, Zdzieszynski S, Sheldon BW, Bishop SR. Coupling of strain, stress, and oxygen non-stoichiometry in thin film Pr0.1Ce0.9O2-δ. NANOSCALE 2016; 8:16499-16510. [PMID: 27604569 DOI: 10.1039/c6nr04083g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Stress and strain in thin films of Pr0.1Ce0.9O2-δ, supported on yttria stabilized zirconia (YSZ) and sapphire substrates, induced by large deviations from oxygen stoichiometry (δ = 0) were investigated by in situ high temperature X-ray diffraction and wafer curvature studies. The measured stresses and strains were correlated with change in δ, measured in situ using optical transmission spectroscopy of defect centers in the films and compared with prior chemical capacitance studies. The coefficient of chemical expansion and elastic modulus values for the films were found to be 18% less than, and 16% greater than in the bulk, respectively. Irreproducible stress and strain during cycling on YSZ substrates was observed and related to microstructural changes as observed by TEM. The enthalpy of defect formation was found to be similar for films supported on sapphire and YSZ, and appeared to decrease with tensile stress, and increase with compressive stress. Larger stresses observed for YSZ supported films as compared to sapphire supported films were found and accounted for by the difference in film orientations.
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Affiliation(s)
- J Sheth
- School of Engineering, Brown University, Providence, RI, USA.
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24
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Zhao Z, Du L, Xu Z, Shao L. Effects of ultrasonic agitation on adhesion strength of micro electroforming Ni layer on Cu substrate. ULTRASONICS SONOCHEMISTRY 2016; 29:1-10. [PMID: 26584978 DOI: 10.1016/j.ultsonch.2015.08.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 05/21/2023]
Abstract
Micro electroforming is an important technology, which is widely used for fabricating micro metal devices in MEMS. The micro metal devices have the problem of poor adhesion strength, which has dramatically influenced the dimensional accuracy of the devices and seriously limited the development of the micro electroforming technology. In order to improve the adhesion strength, ultrasonic agitation method is applied during the micro electroforming process in this paper. To explore the effect of the ultrasonic agitation, micro electroforming experiments were carried out under ultrasonic and ultrasonic-free conditions. The effects of the ultrasonic agitation on the micro electroforming process were investigated by polarization and alternating current (a.c.) impedance methods. The real surface area of the electroforming layer was measured by cyclic voltammetry method. The compressive stress and the crystallite size of the electroforming layer were measured by X-ray Diffraction (XRD) method. The adhesion strength of the electroforming layer was measured by scratch test. The experimental results show that the imposition of the ultrasonic agitation decreases the polarization overpotential and increases the charge transfer process at the electrode-electrolyte interface during the electroforming process. The ultrasonic agitation increases the crystallite size and the real surface area, and reduces the compressive stress. Then the adhesion strength is improved about 47% by the ultrasonic agitation in average. In addition, mechanisms of the ultrasonic agitation improving the adhesion strength are originally explored in this paper. The mechanisms are that the ultrasonic agitation increases the crystallite size, which reduces the compressive stress. The lower the compressive stress is, the larger the adhesion strength is. Furthermore, the ultrasonic agitation increases the real surface area, enhances the mechanical interlocking strength and consequently increases the adhesion strength. This work contributes to fabricating the electroforming layer with large adhesion strength.
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Affiliation(s)
- Zhong Zhao
- Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Liqun Du
- Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, People's Republic of China; Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China.
| | - Zheng Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Ligeng Shao
- School of Electrical Engineering and Information, Dalian Jiaotong University, Dalian, People's Republic of China
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25
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Thermodynamics of deposition flux-dependent intrinsic film stress. Nat Commun 2016; 7:10733. [PMID: 26888311 PMCID: PMC4759625 DOI: 10.1038/ncomms10733] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/15/2016] [Indexed: 11/09/2022] Open
Abstract
Vapour deposition on polycrystalline films can lead to extremely high levels of compressive stress, exceeding even the yield strength of the films. A significant part of this stress has a reversible nature: it disappears when the deposition is stopped and re-emerges on resumption. Although the debate on the underlying mechanism still continues, insertion of atoms into grain boundaries seems to be the most likely one. However, the required driving force has not been identified. To address the problem we analyse, here, the entire film system using thermodynamic arguments. We find that the observed, tremendous stress levels can be explained by the flux-induced entropic effects in the extremely dilute adatom gas on the surface. Our analysis justifies any adatom incorporation model, as it delivers the underlying thermodynamic driving force. Counterintuitively, we also show that the stress levels decrease, if the barrier(s) for adatoms to reach the grain boundaries are decreased.
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26
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Peng XY, Zhou LQ, Li X, Tao XF, Ren LL, Cao WH, Xu GF. Strain study of gold nanomaterials as HR-TEM calibration standard. Micron 2015; 79:46-52. [PMID: 26342191 DOI: 10.1016/j.micron.2015.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 07/23/2015] [Accepted: 07/23/2015] [Indexed: 11/25/2022]
Abstract
This work presents the use of high resolution electron microscopy (HREM) and geometric phase analysis (GPA) to measure the interplanar spacing and strain distribution of three gold nanomaterials, respectively. The results showed that the {111} strain was smaller than the {002} strain for any kind of gold materials at the condition of same measuring method. The 0.65% of {111} strain in gold film measured by HREM (0.26% measured by GPA) was smaller than the {111} strains in two gold particles. The presence of lattice strain was interpreted according to the growth mechanism of metallic thin film. It is deduced that the {111} interplanar spacing of the gold thin film is suitable for high magnification calibration of transmission electron microscopy (TEM) and the gold film is potential to be a new calibration standard of TEM.
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Affiliation(s)
- X Y Peng
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
| | - L Q Zhou
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
| | - X Li
- Division of Nano Metrology and Materials Measurement, National Institute of Metrology, Beijing 100029, China.
| | - X F Tao
- Division of Nano Metrology and Materials Measurement, National Institute of Metrology, Beijing 100029, China
| | - L L Ren
- Division of Nano Metrology and Materials Measurement, National Institute of Metrology, Beijing 100029, China.
| | - W H Cao
- Division of Electricity and Magnetism, National Institute of Metrology, Beijing 100029, China
| | - G F Xu
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
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27
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Luo T, Guo L, Cammarata RC. Morphology evolution during stress relaxation of cobalt films due to dissolution in electrolyte solutions. RSC Adv 2014. [DOI: 10.1039/c4ra06725h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Unlike the stress relaxation of perfect cobalt film (the dotted cure), the relaxation of cobalt film with surface imperfections (such as black pin-holes in above insert) displayed irreversible characters and was suggested to be the result of cobalt dissolution in electrolytes, which could be eliminated by additives such as Cl−.
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Affiliation(s)
- Tianzhi Luo
- Department of Materials Science and Engineering
- Whiting School of Engineering
- Johns Hopkins University
- , USA
- Department of Cell Biology
| | - Lian Guo
- Department of Materials Science and Engineering
- Whiting School of Engineering
- Johns Hopkins University
- , USA
| | - Robert C. Cammarata
- Department of Materials Science and Engineering
- Whiting School of Engineering
- Johns Hopkins University
- , USA
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28
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Chalapat K, Chekurov N, Jiang H, Li J, Parviz B, Paraoanu GS. Self-organized origami structures via ion-induced plastic strain. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:91-95. [PMID: 23023661 DOI: 10.1002/adma.201202549] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 08/16/2012] [Indexed: 06/01/2023]
Abstract
Ion processing of the reactive surface of a free-standing polycrystalline metal film induces a flow of atoms into grain boundaries, resulting in plastic deformation. A thorough experimental and theoretical analysis of this process is presented, along with the demonstration of novel engineering concepts for precisely controlled 3D assembly at micro- and nanoscopic scales.
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29
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Mukhopadhyay A, Tokranov A, Xiao X, Sheldon BW. Stress development due to surface processes in graphite electrodes for Li-ion batteries: A first report. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.01.058] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Frigeri C, Serényi M, Khánh NQ, Csik A, Riesz F, Erdélyi Z, Nasi L, Beke DL, Boyen HG. Relationship between structural changes, hydrogen content and annealing in stacks of ultrathin Si/Ge amorphous layers. NANOSCALE RESEARCH LETTERS 2011; 6:189. [PMID: 21711697 PMCID: PMC3211242 DOI: 10.1186/1556-276x-6-189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 03/01/2011] [Indexed: 05/31/2023]
Abstract
Hydrogenated multilayers (MLs) of a-Si/a-Ge have been analysed to establish the reasons of H release during annealing that has been seen to bring about structural modifications even up to well-detectable surface degradation. Analyses carried out on single layers of a-Si and a-Ge show that H is released from its bond to the host lattice atom and that it escapes from the layer much more efficiently in a-Ge than in a-Si because of the smaller binding energy of the H-Ge bond and probably of a greater weakness of the Ge lattice. This should support the previous hypothesis that the structural degradation of a-Si/a-Ge MLs primary starts with the formation of H bubbles in the Ge layers.
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Affiliation(s)
- Cesare Frigeri
- CNR-IMEM Institute, Parco Area delle Scienze 37/A, 43100 Parma, Italy
| | - Miklós Serényi
- Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Nguyen Quoc Khánh
- Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Attila Csik
- Institute of Nuclear Research of the Hungarian Academy of Sciences, P.O. Box 51, H-4001 Debrecen, Hungary
| | - Ferenc Riesz
- Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Zoltán Erdélyi
- Department of Solid State Physics, University of Debrecen, P.O. Box 2, H-4010 Debrecen, Hungary
| | - Lucia Nasi
- CNR-IMEM Institute, Parco Area delle Scienze 37/A, 43100 Parma, Italy
| | - Dezső László Beke
- Department of Solid State Physics, University of Debrecen, P.O. Box 2, H-4010 Debrecen, Hungary
| | - Hans-Gerd Boyen
- Institute for Materials Research (IMO), Hasselt University, Diepenbeek, Belgium
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31
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Zientarski T. Molecular dynamic simulation of stress development during coalescence of grain in presence of depositing atoms. CRYSTAL RESEARCH AND TECHNOLOGY 2010. [DOI: 10.1002/crat.201000361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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32
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Tabakovic I, Gong J, Riemer S, Venkatasamy V, Kief M. Stress evolution in CoxFe1−x (x=0.33–0.87) electrodeposited films. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.07.100] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33
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Chocyk D, Prószyński A, Gladyszewski G. Effect of annealing on the mechanical behaviour of Au/Cu and Cu/Au bilayers on silicon. CRYSTAL RESEARCH AND TECHNOLOGY 2010. [DOI: 10.1002/crat.201000362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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34
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Fu B, An W, Turner CH, Thompson GB. In situ thin film growth stresses during chemical ordering. PHYSICAL REVIEW LETTERS 2010; 105:096101. [PMID: 20868177 DOI: 10.1103/physrevlett.105.096101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Indexed: 05/29/2023]
Abstract
The in situ growth stress and postgrowth stress relaxation during the L1(0) chemical ordering of Fe0.54Pt0.46 thin films have been characterized. The compressive stress is reduced with an increase in order parameter. The postgrowth stress relaxation rate increased with the order parameter and is rationalized in terms of an increase in the interfacial energy contribution at the grain boundaries because of chemical order. Density functional theory calculations were performed to quantify possible diffusion pathways and binding energies for Fe and Pt that may mitigate surface migration.
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Affiliation(s)
- B Fu
- Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0202, USA
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35
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Fillon A, Abadias G, Michel A, Jaouen C, Villechaise P. Influence of phase transformation on stress evolution during growth of metal thin films on silicon. PHYSICAL REVIEW LETTERS 2010; 104:096101. [PMID: 20366996 DOI: 10.1103/physrevlett.104.096101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Indexed: 05/29/2023]
Abstract
In situ stress measurements during two-dimensional growth of low mobility metal films on amorphous Si were used to demonstrate the impact of interface reactivity and phase transformation on stress evolution. Using Mo1-xSix films as examples, the results show that the tensile stress rise, which develops after the film has become crystalline, is correlated with an increase in lateral grain size. The origin of the tensile stress is attributed to the volume change resulting from the alloy crystallization, which occurs at a concentration-dependent critical thickness.
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Affiliation(s)
- A Fillon
- Institut P', CNRS-Université de Poitiers-ENSMA, Département Physique et Mécanique des Matériaux, SP2MI-Téléport 2, F86962 Futuroscope-Chasseneuil cedex, France
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36
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Shin JW, Chason E. Compressive stress generation in sn thin films and the role of grain boundary diffusion. PHYSICAL REVIEW LETTERS 2009; 103:056102. [PMID: 19792516 DOI: 10.1103/physrevlett.103.056102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 03/04/2009] [Indexed: 05/28/2023]
Abstract
Stress evolution in high mobility Sn thin films was measured during electrodeposition and electrochemical etching to understand the roles of grain boundary diffusion and surface conditions in controlling stress. During deposition, the stress reaches a steady-state compressive value that depends on the growth rate. When the deposition or etching conditions were changed abruptly, reversible transients were observed that depend on the film thickness. The results are interpreted in terms of a model based on diffusion of atoms into the grain boundary driven by the chemical potential at the surface.
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Affiliation(s)
- Jae Wook Shin
- Brown University, Providence, Rhode Island 02912, USA
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37
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Leib J, Mönig R, Thompson CV. Direct evidence for effects of grain structure on reversible compressive deposition stresses in polycrystalline gold films. PHYSICAL REVIEW LETTERS 2009; 102:256101. [PMID: 19659098 DOI: 10.1103/physrevlett.102.256101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Indexed: 05/28/2023]
Abstract
A component of the compressive stress that develops during deposition of polycrystalline thin films reversibly changes during interruptions of growth. The mechanism responsible for this phenomenon has been the subject of much recent speculation and experimental work. In this Letter, we have varied the in-plane grain size of columnar polycrystalline gold films with a fixed thickness, by varying their thermal history. Without a vacuum break, the stress in these films was then measured in situ during growth and during interruptions in growth. Homoepitaxial gold films were similarly characterized as part of this study. The inverse of the in-plane grain size and the corresponding reversible stress change were found to be proportional, with zero reversible stress change observed for infinite grain size (homoepitaxial films). These results demonstrate a clear role of grain size in the reversible changes in gold films.
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Affiliation(s)
- J Leib
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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38
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Pletea M, Koch R, Wendrock H, Kaltofen R, Schmidt OG. In situ stress evolution during and after sputter deposition of Al thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:225008. [PMID: 21715772 DOI: 10.1088/0953-8984/21/22/225008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The stress, growth, and morphology evolution of Al thin films up to 300 nm thick, sputter deposited at a constant rate of 0.04 nm s(-1) onto thermally oxidized Si(100) substrates have been investigated for various sputter pressures in the range from 0.05 to 6 Pa. The stress evolution has been studied during and after the film deposition by means of in situ substrate curvature measurements using an optical two-beam deflection method. In order to obtain insight into the mechanisms of stress generation and relaxation, the microstructure of the films was investigated by scanning electron microscopy, focused-ion-beam microscopy, and atomic force microscopy. The stress evolution during the early stage of deposition of films is consistent with the Volmer-Weber growth mode known for metals with high adatom mobility. For thicker films, the compressive stress increases in the sputter pressure range of 0.05-0.5 Pa, whereas at even higher sputter pressures a transition from compressive to tensile stress takes place. This transition is correlated with a change from a relatively dense to a more porous microstructure characterized by decreasing mass density and increasing electrical resistivity with increasing sputter pressure. The dependence of the stress and microstructure on the sputter pressure can be consistently understood through a combination of the stress mechanisms for vapor and sputter deposited films proposed in the literature.
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Affiliation(s)
- M Pletea
- Institute for Integrative Nanosciences, IFW-Dresden, Helmholtzstraße 20, D-01069 Dresden, Germany
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39
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Houser JE, Hebert KR. The role of viscous flow of oxide in the growth of self-ordered porous anodic alumina films. NATURE MATERIALS 2009; 8:415-420. [PMID: 19363477 DOI: 10.1038/nmat2423] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 03/10/2009] [Indexed: 05/27/2023]
Abstract
Porous anodic alumina (PAA) films are widely used as templates for functional nanostructures, because of the high regularity and controllability of the pore morphology. However, growth mechanisms have not yet been developed that can explain quantitative relationships between processing conditions and oxide layer geometry. Here, we present a model for steady-state growth of these amorphous films, incorporating the novel feature that metal and oxygen ions are transported by coupled electrical migration and viscous flow. The oxide flow in the model arises near the film-solution interface at the pore bottoms, in response to the constraint of volume conservation. The hypothesis of viscous flow was successfully validated through detailed comparisons to observations of the motion of tungsten tracers in the film. Predictions of localized tensile stress near nanoscale ridges at the metal-film interface were supported by observations of voids at these sites. We suggest that the ordering of PAA may be explained by a mechanism in which metal-film interface motion is regulated by the combination of ionic migration in the oxide and stress-driven interface diffusion of metal atoms.
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Affiliation(s)
- Jerrod E Houser
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
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40
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Chocyk D, Zientarski T. Molecular dynamics simulation of stress and grain evolution. Mol Phys 2008. [DOI: 10.1080/00268970802126590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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41
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Rost MJ. In situ real-time observation of thin film deposition: roughening, zeno effect, grain boundary crossing barrier, and steering. PHYSICAL REVIEW LETTERS 2007; 99:266101. [PMID: 18233590 DOI: 10.1103/physrevlett.99.266101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Indexed: 05/25/2023]
Abstract
We report on the first atomic-scale real-time in situ investigation of the growth of a polycrystalline gold film during its deposition performed with a scanning tunneling microscope. Continuously scanning while depositing the film enables the direct observation of atomic processes. The grain boundaries play a crucial role in the evolving film structure, as they initiate mound formation, thereby significantly increasing the film roughness. A possible additional roughness increase comes from atom steering, which also can delay the film closure in the early stages during film growth.
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Affiliation(s)
- M J Rost
- Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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42
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Pao CW, Foiles SM, Webb EB, Srolovitz DJ, Floro JA. Thin film compressive stresses due to adatom insertion into grain boundaries. PHYSICAL REVIEW LETTERS 2007; 99:036102. [PMID: 17678297 DOI: 10.1103/physrevlett.99.036102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Indexed: 05/16/2023]
Abstract
Atomic simulations of the growth of polycrystalline Ni demonstrate that deposited atoms incorporate into the film at boundaries, resulting in compressive stress generation. Incorporated atoms can also leave the boundaries and thus relieve compressive stress. This leads to a complex interplay between growth stress, adatom incorporation, and surface structure. A simple, theoretical model that accounts for grain size effects is proposed and is in good agreement with simulation results.
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Affiliation(s)
- Chun-Wei Pao
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
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43
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Tello JS, Bower AF, Chason E, Sheldon BW. Kinetic model of stress evolution during coalescence and growth of polycrystalline thin films. PHYSICAL REVIEW LETTERS 2007; 98:216104. [PMID: 17677789 DOI: 10.1103/physrevlett.98.216104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2006] [Revised: 11/02/2006] [Indexed: 05/16/2023]
Abstract
We outline a simple continuum model of the stresses that result from the coalescence and growth of islands during deposition of a polycrystalline thin film. Our model includes a detailed description of attractive forces between neighboring islands, and also accounts for mass transport along surfaces and grain boundaries. The finite element method is used to calculate the island shape changes as well as the stresses and displacements in the film during the growth process. The model reproduces several experimental observations, including the variation of stress with film thickness, the range of observed growth stresses, and the effects of deposition flux and grain boundary diffusivity on stress.
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Affiliation(s)
- Juan S Tello
- Division of Engineering, Brown University, Providence, Rhode Island 02912, USA.
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44
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Zandbergen HW, Pao CW, Srolovitz DJ. Dislocation injection, reconstruction, and atomic transport on {001} Au terraces. PHYSICAL REVIEW LETTERS 2007; 98:036103. [PMID: 17358698 DOI: 10.1103/physrevlett.98.036103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Indexed: 05/14/2023]
Abstract
High-resolution electron microscopy investigations of Au films show that adatoms on (100) surfaces insert into the underlying terrace to form surface dislocations. This injection readily occurs when the number of adatoms on a terrace is approximately 20 atoms or less. The surface dislocation glides along the terrace, but is repelled from the edges. The dislocation escapes by squeezing out in the dislocation line direction (not gliding out the terrace edge). Atomistic simulations confirm the dislocation stability, easy glide along the terrace and trapping at the terrace edge. These results have profound implications for film growth.
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Affiliation(s)
- Henny W Zandbergen
- National Centre for HREM, Kavli Centre of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
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45
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Pao CW, Srolovitz DJ. Stress and morphology evolution during island growth. PHYSICAL REVIEW LETTERS 2006; 96:186103. [PMID: 16712376 DOI: 10.1103/physrevlett.96.186103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Indexed: 05/09/2023]
Abstract
We performed a series of hybrid molecular-dynamics simulations of island growth on a substrate and monitored island stress evolution for several different island/substrate interfacial energies. Smaller (larger) interfacial energy yields islands with a stronger (weaker) compressive stress-thickness product. We present analytical results that suggest that the stress-thickness product is a linear function of the substrate coverage, with slope equal to minus the substrate surface stress, if the island is in mechanical equilibrium, and verify these results with simulation data.
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Affiliation(s)
- Chun-Wei Pao
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
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46
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Friesen C, Thompson CV. Comment on "Compressive stress in polycrystalline Volmer-Weber films". PHYSICAL REVIEW LETTERS 2005; 95:229601; author reply 229602. [PMID: 16384272 DOI: 10.1103/physrevlett.95.229601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Indexed: 05/05/2023]
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47
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Koch R, Hu D, Das AK. Compressive stress in polycrystalline volmer-weber films. PHYSICAL REVIEW LETTERS 2005; 94:146101. [PMID: 15904079 DOI: 10.1103/physrevlett.94.146101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Indexed: 05/02/2023]
Abstract
The Volmer-Weber mode for growing polycrystalline films, which comprises island, network, and channel stages before the films become continuous, is well known for its complex stress behavior with compressive and tensile stress alternating in the initial three growth stages. Recently, two new mechanisms for the compressive stress have been proposed [Phys. Rev. Lett. 88, 156103 (2002); 89, 126103 (2002)], which account for the reversibility of stress generation and relaxation. We show that the two mechanisms play only minor roles for the development of compressive stress, which is confirmed to be due to capillarity effects in the precoalescence stage.
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Affiliation(s)
- R Koch
- Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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48
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Chocyk D, Zientarski T, Proszynski A, Pienkos T, Gladyszewski L, Gladyszewski G. Evolution of stress and structure in Cu thin films. CRYSTAL RESEARCH AND TECHNOLOGY 2005. [DOI: 10.1002/crat.200410376] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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49
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Friesen C, Thompson CV. Correlation of stress and atomic-scale surface roughness evolution during intermittent homoepitaxial growth of (111)-oriented Ag and Cu. PHYSICAL REVIEW LETTERS 2004; 93:056104. [PMID: 15323716 DOI: 10.1103/physrevlett.93.056104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Indexed: 05/24/2023]
Abstract
Stress evolution during intermittent homoepitaxial growth of (111)-oriented Cu and Ag thin films has been studied. A tensile stress change is observed when growth is stopped, but the change is reversed when growth is resumed. Reflection high energy electron diffraction analysis of the atomic scale surface roughness during intermittent growth demonstrates a strong correlation between the surface structure and reversible stress evolution. The results are discussed in terms of an evolving surface defect population.
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Affiliation(s)
- C Friesen
- Department of Materials and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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50
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Floro JA, Kotula PG, Seel SC, Srolovitz DJ. Origins of growth stresses in amorphous semiconductor thin films. PHYSICAL REVIEW LETTERS 2003; 91:096101. [PMID: 14525195 DOI: 10.1103/physrevlett.91.096101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2003] [Indexed: 05/24/2023]
Abstract
Stress evolution during deposition of amorphous Si and Ge thin films is remarkably similar to that observed for polycrystalline films. Amorphous semiconductors were used as model materials to study the origins of deposition stresses in continuous films, where suppression of both strain relaxation and epitaxial strain inheritance provides considerable simplification. Our data show that bulk compression is established by surface stress, while a subsequent return to tensile stress arises from elastic coalescence processes occurring on the kinetically roughened surface.
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Affiliation(s)
- J A Floro
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1415, USA
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