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Kilpatrick JI, Kargin E, Rodriguez BJ. Comparing the performance of single and multifrequency Kelvin probe force microscopy techniques in air and water. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:922-943. [PMID: 36161252 PMCID: PMC9490074 DOI: 10.3762/bjnano.13.82] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/04/2022] [Indexed: 06/16/2023]
Abstract
In this paper, we derive and present quantitative expressions governing the performance of single and multifrequency Kelvin probe force microscopy (KPFM) techniques in both air and water. Metrics such as minimum detectable contact potential difference, minimum required AC bias, and signal-to-noise ratio are compared and contrasted both off resonance and utilizing the first two eigenmodes of the cantilever. These comparisons allow the reader to quickly and quantitatively identify the parameters for the best performance for a given KPFM-based experiment in a given environment. Furthermore, we apply these performance metrics in the identification of KPFM-based modes that are most suitable for operation in liquid environments where bias application can lead to unwanted electrochemical reactions. We conclude that open-loop multifrequency KPFM modes operated with the first harmonic of the electrostatic response on the first eigenmode offer the best performance in liquid environments whilst needing the smallest AC bias for operation.
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Affiliation(s)
- Jason I Kilpatrick
- School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Emrullah Kargin
- School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Brian J Rodriguez
- School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
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Ghanbari Kouchaksaraei M, Bahrami A. High-resolution compositional mapping of surfaces in non-contact atomic force microscopy by a new multi-frequency excitation. Ultramicroscopy 2021; 227:113317. [PMID: 34119854 DOI: 10.1016/j.ultramic.2021.113317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 04/13/2021] [Accepted: 05/09/2021] [Indexed: 10/21/2022]
Abstract
In this paper, a new multi-frequency excitation method based on combination resonance is introduced to enhance the non-contact atomic force microscopy performance. In combination resonance, excitation frequencies are selected so that summation/subtraction of excitation frequencies is close to the natural frequencies of the microcantilever. Due to the nonlinear nature of this method, the probe response to excitation is very sensitive to change in tip-sample forces. This could be used to generate high-resolution compositional mapping and topographical images of the surface. The present study reveals that both amplitude and phase shift of the combination resonance are sensitive to change in parameters such as Hamaker constant, damping coefficient, Young's modulus and tip-sample initial distance. It is observed that because of high sensitivity to Hamaker constant a small change in the surface material leads to considerable variations in amplitude and phase shift. This sensitivity is employed to improve compositional mapping of the surface materials. It is also found out that the response amplitude in the combination resonance is very sensitive to change in the tip-sample initial distance. This sensitivity may be used to reduce the vertical noise and increase image resolution, especially in environments with low quality factors. Overall, using this technique the image contrast increases significantly and high resolution compositional mapping of surfaces is achieved.
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Affiliation(s)
| | - Arash Bahrami
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
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Garcia R. Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications. Chem Soc Rev 2020; 49:5850-5884. [PMID: 32662499 DOI: 10.1039/d0cs00318b] [Citation(s) in RCA: 161] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Fast, high-resolution, non-destructive and quantitative characterization methods are needed to develop materials with tailored properties at the nanoscale or to understand the relationship between mechanical properties and cell physiology. This review introduces the state-of-the-art force microscope-based methods to map at high-spatial resolution the elastic and viscoelastic properties of soft materials. The experimental methods are explained in terms of the theories that enable the transformation of observables into material properties. Several applications in materials science, molecular biology and mechanobiology illustrate the scope, impact and potential of nanomechanical mapping methods.
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Affiliation(s)
- Ricardo Garcia
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
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Enhancing phase contrast for bimodal AFM imaging in low quality factor environments. Ultramicroscopy 2019; 204:18-26. [DOI: 10.1016/j.ultramic.2019.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 03/23/2019] [Accepted: 05/12/2019] [Indexed: 11/20/2022]
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Soliman M, Ding Y, Tetard L. Nanoscale subsurface imaging. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:173001. [PMID: 28140334 DOI: 10.1088/1361-648x/aa5b4a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ability to probe structures and functional properties of complex systems at the nanoscale, both at their surface and in their volume, has drawn substantial attention in recent years. Besides detecting heterogeneities, cracks and defects below the surface, more advanced explorations of chemical or electrical properties are of great interest. In this article, we review some approaches developed to explore heterogeneities below the surface, including recent progress in the different aspects of metrology in optics, electron microscopy, and scanning probe microscopy. We discuss the principle and mechanisms of image formation associated with each technique, including data acquisition, data analysis and modeling for nanoscale structural and functional imaging. We highlight the advances based on atomic force microscopy (AFM). Our discussion first introduces methods providing structural information of the buried structures, such as position in the volume and geometry. Next we present how functional properties including conductivity, capacitance, and composition can be extracted from the modalities available to date and how they could eventually enable tomography reconstructions of systems such as overlay structures in transistors or living systems. Finally we propose a perspective regarding the outstanding challenges and needs to push the field forward.
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Affiliation(s)
- M Soliman
- NanoScience Technology Center, 12424 Research Parkway, University of Central Florida, Orlando, FL, 32826, United States of America. Materials Science and Engineering, 12760 Pegasus Drive, University of Central Florida, Orlando, FL, 32816, United States of America
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Somnath S, Collins L, Matheson MA, Sukumar SR, Kalinin SV, Jesse S. Imaging via complete cantilever dynamic detection: general dynamic mode imaging and spectroscopy in scanning probe microscopy. NANOTECHNOLOGY 2016; 27:414003. [PMID: 27607339 DOI: 10.1088/0957-4484/27/41/414003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We develop and implement a multifrequency spectroscopy and spectroscopic imaging mode, referred to as general dynamic mode (GDM), that captures the complete spatially- and stimulus dependent information on nonlinear cantilever dynamics in scanning probe microscopy (SPM). GDM acquires the cantilever response including harmonics and mode mixing products across the entire broadband cantilever spectrum as a function of excitation frequency. GDM spectra substitute the classical measurements in SPM, e.g. amplitude and phase in lock-in detection. Here, GDM is used to investigate the response of a purely capacitively driven cantilever. We use information theory techniques to mine the data and verify the findings with governing equations and classical lock-in based approaches. We explore the dependence of the cantilever dynamics on the tip-sample distance, AC and DC driving bias. This approach can be applied to investigate the dynamic behavior of other systems within and beyond dynamic SPM. GDM is expected to be useful for separating the contribution of different physical phenomena in the cantilever response and understanding the role of cantilever dynamics in dynamic AFM techniques.
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Affiliation(s)
- Suhas Somnath
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Perrino AP, Ryu YK, Amo CA, Morales MP, Garcia R. Subsurface imaging of silicon nanowire circuits and iron oxide nanoparticles with sub-10 nm spatial resolution. NANOTECHNOLOGY 2016; 27:275703. [PMID: 27232523 DOI: 10.1088/0957-4484/27/27/275703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Non-destructive subsurface characterization of nanoscale structures and devices is of significant interest in nanolithography and nanomanufacturing. In those areas, the accurate location of the buried structures and their nanomechanical properties are relevant for optimization of the nanofabrication process and the functionality of the system. Here we demonstrate the capabilities of bimodal and trimodal force microscopy for imaging silicon nanowire devices buried under an ultrathin polymer film. We resolve the morphology and periodicities of silicon nanowire pairs. We report a spatial resolution in the sub-10 nm range for nanostructures buried under a 70 nm thick polymer film. By using numerical simulations we explain the role of the excited modes in the subsurface imaging process. Independent of the bimodal or trimodal atomic force microscopy approach, the fundamental mode is the most suitable for tracking the topography while the higher modes modulate the interaction of the tip with the buried nanostructures and provide subsurface contrast.
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Affiliation(s)
- A P Perrino
- Instituto de Ciencia de Materiales de Madrid, CSIC c/Sor Juna Ines de la Cruz 3, 28049 Madrid, Spain
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Eslami B, Solares SD. Imaging of surface nanobubbles by atomic force microscopy in liquids: Influence of drive frequency on the characterization of ultrasoft matter. Microsc Res Tech 2016; 80:41-49. [DOI: 10.1002/jemt.22711] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/23/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Babak Eslami
- Department of Mechanical and Aerospace Engineering; The George Washington University; 800 22nd Street NW, Suite 3000 Washington, DC 20052 USA
| | - Santiago D. Solares
- Department of Mechanical and Aerospace Engineering; The George Washington University; 800 22nd Street NW, Suite 3000 Washington, DC 20052 USA
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Developments in dynamic atomic force microscopy techniques to characterize viscoelastic behaviors of food materials at the nanometer-scale. Curr Opin Food Sci 2016. [DOI: 10.1016/j.cofs.2016.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Meier T, Eslami B, Solares SD. Multifrequency force microscopy using flexural and torsional modes by photothermal excitation in liquid: atomic resolution imaging of calcite (1014). NANOTECHNOLOGY 2016; 27:085702. [PMID: 26807504 DOI: 10.1088/0957-4484/27/8/085702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We introduce a new multifrequency atomic force microscopy (AFM) method which involves the excitation of flexural and torsional eigenmodes of the microcantilever probe in liquid environments. The flexural and torsional deflection signals are mostly decoupled in the majority of commercial AFM setups, so they can be relatively easily recorded and processed. The use of torsional modes provides additional surface information at the atomic scale, with respect to flexural mode imaging alone, although the flexural modes are the only ones capable of 'true' atomic resolution imaging. In our experiments, the torsional modes are shown to be particularly sensitive to protruding oxygen surface atoms on the calcite (1014) plane. The high lateral resolution capability of the flexural modes, combined with the high sensitivity of the torsional modes to specific surface features in liquid environments, can thus offer the means of observing chemical contrast at the atomic level using purely mechanical measurement AFM techniques, even in the absence of tip functionalization.
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Affiliation(s)
- Tobias Meier
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052, USA
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Solares SD, An S, Long CJ. Multi-frequency tapping-mode atomic force microscopy beyond three eigenmodes in ambient air. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:1637-48. [PMID: 25383276 PMCID: PMC4222484 DOI: 10.3762/bjnano.5.175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/31/2014] [Indexed: 05/12/2023]
Abstract
We present an exploratory study of multimodal tapping-mode atomic force microscopy driving more than three cantilever eigenmodes. We present tetramodal (4-eigenmode) imaging experiments conducted on a thin polytetrafluoroethylene (PTFE) film and computational simulations of pentamodal (5-eigenmode) cantilever dynamics and spectroscopy, focusing on the case of large amplitude ratios between the fundamental eigenmode and the higher eigenmodes. We discuss the dynamic complexities of the tip response in time and frequency space, as well as the average amplitude and phase response. We also illustrate typical images and spectroscopy curves and provide a very brief description of the observed contrast. Overall, our findings are promising in that they help to open the door to increasing sophistication and greater versatility in multi-frequency AFM through the incorporation of a larger number of driven eigenmodes, and in highlighting specific future research opportunities.
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Affiliation(s)
- Santiago D Solares
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States; current address: Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052, United States
- Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, United States
| | - Sangmin An
- Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, United States
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
| | - Christian J Long
- Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, United States
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
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