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Antić Ž, Kuzman S, Đorđević V, Dramićanin MD, Thundat T. White- and blue-light-emitting dysprosium(III) and terbium(III)-doped gadolinium titanate phosphors. LUMINESCENCE 2016; 32:539-544. [DOI: 10.1002/bio.3210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Ž. Antić
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton T6G 2V4 Canada
| | - S. Kuzman
- Vinča Institute of Nuclear Sciences; University of Belgrade; P.O. Box 522 11001 Belgrade Serbia
| | - V. Đorđević
- Vinča Institute of Nuclear Sciences; University of Belgrade; P.O. Box 522 11001 Belgrade Serbia
| | - M. D. Dramićanin
- Vinča Institute of Nuclear Sciences; University of Belgrade; P.O. Box 522 11001 Belgrade Serbia
| | - T. Thundat
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton T6G 2V4 Canada
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2
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Etayash H, McGee AR, Kaur K, Thundat T. Nanomechanical sandwich assay for multiple cancer biomarkers in breast cancer cell-derived exosomes. Nanoscale 2016; 8:15137-41. [PMID: 27492928 DOI: 10.1039/c6nr03478k] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The use of exosomes as cancer diagnostic biomarkers is technically limited by their size, heterogeneity and the need for extensive purification and labelling. We report the use of cantilever arrays for simultaneous detection of multiple exosomal surface-antigens with high sensitivity and selectivity. Exosomes from breast cancer were selectively identified by detecting over-expressed membrane-proteins CD24, CD63, and EGFR. Excellent selectivity however, was achieved when targeting the cell-surface proteoglycan, Glypican-1 at extraordinary limits (∼200 exosomes per mL, ∼0.1 pg mL(-1)).
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Affiliation(s)
- H Etayash
- Faculty of Pharmacy and Pharmaceutical Sciences University of Alberta, Edmonton, Alberta T6G 2E1, Canada and Department of Chemical and Materials Engineering University of Alberta, Edmonton, T6G 2V4, Alberta, Canada.
| | - A R McGee
- Department of Chemical and Materials Engineering University of Alberta, Edmonton, T6G 2V4, Alberta, Canada.
| | - K Kaur
- Faculty of Pharmacy and Pharmaceutical Sciences University of Alberta, Edmonton, Alberta T6G 2E1, Canada and Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618-1908, USA
| | - T Thundat
- Department of Chemical and Materials Engineering University of Alberta, Edmonton, T6G 2V4, Alberta, Canada.
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Ghoraishi MS, Hawk JE, Phani A, Khan MF, Thundat T. Clustering mechanism of ethanol-water mixtures investigated with photothermal microfluidic cantilever deflection spectroscopy. Sci Rep 2016; 6:23966. [PMID: 27046089 PMCID: PMC4820714 DOI: 10.1038/srep23966] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/15/2016] [Indexed: 11/09/2022] Open
Abstract
The infrared-active (IR) vibrational mode of ethanol (EtOH) associated with the asymmetrical stretching of the C-C-O bond in pico-liter volumes of EtOH-water binary mixtures is calorimetrically measured using photothermal microfluidic cantilever deflection spectroscopy (PMCDS). IR absorption by the confined liquid results in wavelength dependent cantilever deflections, thus providing a complementary response to IR absorption revealing a complex dipole moment dependence on mixture concentration. Solvent-induced blue shifts of the C-C-O asymmetric vibrational stretch for both anti and gauche conformers of EtOH were precisely monitored for EtOH concentrations ranging from 20-100% w/w. Variations in IR absorption peak maxima show an inverse dependence on induced EtOH dipole moment (μ) and is attributed to the complex clustering mechanism of EtOH-water mixtures.
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Affiliation(s)
- M. S. Ghoraishi
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - J. E. Hawk
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - Arindam Phani
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - M. F. Khan
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - T. Thundat
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
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Tetard L, Passian A, Farahi RH, Thundat T, Davison BH. Opto-nanomechanical spectroscopic material characterization. Nat Nanotechnol 2015; 10:870-7. [PMID: 26258550 DOI: 10.1038/nnano.2015.168] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 07/01/2015] [Indexed: 05/27/2023]
Abstract
The non-destructive, simultaneous chemical and physical characterization of materials at the nanoscale is an essential and highly sought-after capability. However, a combination of limitations imposed by Abbe diffraction, diffuse scattering, unknown subsurface, electromagnetic fluctuations and Brownian noise, for example, have made achieving this goal challenging. Here, we report a hybrid approach for nanoscale material characterization based on generalized nanomechanical force microscopy in conjunction with infrared photoacoustic spectroscopy. As an application, we tackle the outstanding problem of spatially and spectrally resolving plant cell walls. Nanoscale characterization of plant cell walls and the effect of complex phenotype treatments on biomass are challenging but necessary in the search for sustainable and renewable bioenergy. We present results that reveal both the morphological and compositional substructures of the cell walls. The measured biomolecular traits are in agreement with the lower-resolution chemical maps obtained with infrared and confocal Raman micro-spectroscopies of the same samples. These results should prove relevant in other fields such as cancer research, nanotoxicity, and energy storage and production, where morphological, chemical and subsurface studies of nanocomposites, nanoparticle uptake by cells and nanoscale quality control are in demand.
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Affiliation(s)
- L Tetard
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Passian
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics, University of Tennessee, Knoxville, Tennessee 37996-1200, USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - R H Farahi
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T Thundat
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - B H Davison
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
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Soin N, Boyer D, Prashanthi K, Sharma S, Narasimulu AA, Luo J, Shah TH, Siores E, Thundat T. Exclusive self-aligned β-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion. Chem Commun (Camb) 2015; 51:8257-60. [PMID: 25874745 DOI: 10.1039/c5cc01688f] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Self-polarised poly(vinylidene fluoride), (PVDF), films were prepared via a facile phase-inversion technique wherein the polymorphism of the films was controlled from exclusive α- (>90%) to β-phase (>98%) by simply varying the quenching temperature from 100 °C to -20 °C, respectively. At low temperatures, the β-phase crystallites were found to be self-aligned, with the PVDF thin films possessing a high piezoelectric coefficient of up to -49.6 pm V(-1). The extraordinarily high β-phase and piezoelectric coefficient of these PVDF films make them suitable for electroactive and energy harvesting applications.
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Affiliation(s)
- N Soin
- Inst. Renew. Energy & Environ. Technol. Uni. of Bolton, Deane Road, Bolton, BL3 5AB, UK.
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Khorshidi B, Thundat T, Fleck BA, Sadrzadeh M. Thin film composite polyamide membranes: parametric study on the influence of synthesis conditions. RSC Adv 2015. [DOI: 10.1039/c5ra08317f] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Analysis of strong interaction between monomers concentrations in interfacial polymerization reaction provides valuable guidelines for making a wide range of salt rejecting membranes.
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Affiliation(s)
- B. Khorshidi
- Department of Mechanical Engineering
- University of Alberta
- Edmonton
- Canada
| | - T. Thundat
- Department of Chemical and Material Engineering
- University of Alberta
- Edmonton
- Canada
| | - B. A. Fleck
- Department of Mechanical Engineering
- University of Alberta
- Edmonton
- Canada
| | - M. Sadrzadeh
- Department of Mechanical Engineering
- University of Alberta
- Edmonton
- Canada
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7
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Biswas TS, Miriyala N, Doolin C, Liu X, Thundat T, Davis JP. Femtogram-scale photothermal spectroscopy of explosive molecules on nanostrings. Anal Chem 2014; 86:11368-72. [PMID: 25329453 DOI: 10.1021/ac503318e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate detection of femtogram-scale quantities of the explosive molecule 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) via combined nanomechanical photothermal spectroscopy and mass desorption. Photothermal spectroscopy provides a spectroscopic fingerprint of the molecule, which is unavailable using mass adsorption/desorption alone. Our measurement, based on thermomechanical measurement of silicon nitride nanostrings, represents the highest mass resolution ever demonstrated via nanomechanical photothermal spectroscopy. This detection scheme is quick, label-free, and is compatible with parallelized molecular analysis of multicomponent targets.
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Affiliation(s)
- T S Biswas
- Department of Physics, University of Alberta , Edmonton, Alberta T6G 2E9, Canada
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8
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Prashanthi K, Thundat T. In situ study of electric field-induced magnetization in multiferroic BiFeO(3) nanowires. Scanning 2014; 36:224-230. [PMID: 23637049 DOI: 10.1002/sca.21092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/18/2013] [Indexed: 06/02/2023]
Abstract
In this work, we have studied electric field-induced magnetization effect of multiferroic BiFeO3 (BFO) nanowires in situ using magnetic force microscopy (MFM). Changes in magnetic domain contrast have been observed in the MFM phase images under applied electric potential, which indicate local magnetoelectric (ME) coupling in the nanowires. The values of saturation and magnetization at different applied electric fields were evaluated. These results suggest that one-dimensional multiferroic BFO nanowires are potential candidates for realizing multiferroic devices at nanoscale with unique functionalities.
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Affiliation(s)
- K Prashanthi
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - T Thundat
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada
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9
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Djokić S, Djokić N, Guthy C, Thundat T. Deposition of copper, silver and gold from aqueous solutions onto germanium substrates via galvanic displacement. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.07.099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Single-particle interactions hold the promise of nanometer-scale devices in areas such as data communications and storage, nanolithography, waveguides, renewable energy and therapeutics. We propose that the collective electronic properties possessed by noble metal nanoparticles may be exploited for device actuation via the unapparent mechanism of plasmon-assisted heat generation and flux. The temperature dependence of the dielectric function and the thermal transport properties of the particles play the central role in the feasibility of the thermally-actuated system, however the behavior of these thermoplasmonic processes is unclear. We experimentally and computationally analyzed modulation via thermoplasmonic processes on a test system of gold (Au) nano-islands. Modulation and energy transport in discontinuous domains exhibited quantitatively different characteristics compared to thin films. The results have implications for all surface plasmon based nano-devices where inevitable small-scale thermal processes are present.
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Affiliation(s)
- A L Lereu
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123, USA
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Sohrabi A, Shaibani P, Etayash H, Kaur K, Thundat T. Sustained drug release and antibacterial activity of ampicillin incorporated poly(methyl methacrylate)–nylon6 core/shell nanofibers. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.03.046] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The stability of food and water supplies is widely recognized as a global issue of fundamental importance. Sensor development for food and water safety by nonconventional assays continues to overcome technological challenges. The delicate balance between attaining adequate limits of detection, chemical fingerprinting of the target species, dealing with the complex food matrix, and operating in difficult environments are still the focus of current efforts. While the traditional pursuit of robust recognition methods remains important, emerging engineered nanomaterials and nanotechnology promise better sensor performance but also bring about new challenges. Both advanced receptor-based sensors and emerging non-receptor-based physical sensors are evaluated for their critical challenges toward out-of-laboratory applications.
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Affiliation(s)
- R H Farahi
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123, USA
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13
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Lereu AL, Passian A, Farahi RH, Abel-Tiberini L, Tetard L, Thundat T. Spectroscopy and imaging of arrays of nanorods toward nanopolarimetry. Nanotechnology 2012; 23:045701. [PMID: 22214608 DOI: 10.1088/0957-4484/23/4/045701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The polarization dependence of the optical scattering properties of two-dimensional arrays of metal nanostructures with sub-wavelength dimensions (nanoantennas) has been investigated. Arrays of 500 nm × 100 nm gold nanorods covering a 100 × 100 µm(2) area were fabricated with varying orientations on an electrically conductive substrate. The experimental and computational analysis of the angularly organized nanorods suggest potential use toward the development of an integrated polarimeter. Using the gold nanorods on a transparent substrate as a preliminary system, we show that in the proper spectral range the scattering properties of the structures may be tuned for such an application.
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Affiliation(s)
- A L Lereu
- CINaM CNRS Campus de Luminy, Marseille, France
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14
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Tetard L, Passian A, Farahi RH, Davison BH, Jung S, Ragauskas AJ, Lereu AL, Thundat T. Nanometrology of delignified Populus using mode synthesizing atomic force microscopy. Nanotechnology 2011; 22:465702. [PMID: 22024985 DOI: 10.1088/0957-4484/22/46/465702] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The study of the spatially resolved physical and compositional properties of materials at the nanoscale is increasingly challenging due to the level of complexity of biological specimens such as those of interest in bioenergy production. Mode synthesizing atomic force microscopy (MSAFM) has emerged as a promising metrology tool for such studies. It is shown that, by tuning the mechanical excitation of the probe-sample system, MSAFM can be used to dynamically investigate the multifaceted complexity of plant cells. The results are argued to be of importance both for the characteristics of the invoked synthesized modes and for accessing new features of the samples. As a specific system to investigate, we present images of Populus, before and after a holopulping treatment, a crucial step in the biomass delignification process.
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Affiliation(s)
- L Tetard
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 3783, USA
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15
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Tetard L, Passian A, Farahi RH, Davison BH, Thundat T. Optomechanical spectroscopy with broadband interferometric and quantum cascade laser sources. Opt Lett 2011; 36:3251-3253. [PMID: 21847224 DOI: 10.1364/ol.36.003251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The spectral tunability of semiconductor-metal multilayer structures can provide a channel for the conversion of light into useful mechanical actuation. Responses of suspended silicon, silicon nitride, chromium, gold, and aluminum microstructures are shown to be utilized as a detector for visible and IR spectroscopy. Both dispersive and interferometric approaches are investigated to delineate the potential use of the structures in spatially resolved spectroscopy and spectrally resolved microscopy. The thermoplasmonic, spectral absorption, interference effects, and the associated energy deposition that contributes to the mechanical response are discussed to describe the potential of optomechanical detection in future integrated spectrometers.
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Affiliation(s)
- L Tetard
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 USA
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Lindsay SM, Thundat T, Nagahara L. Adsorbate deformation as a contrast mechanism in STM images of biopolymers in an aqueous environment: images of the unstained, hydrated DNA double helix. J Microsc 2011. [DOI: 10.1111/j.1365-2818.1988.tb01381.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tetard L, Passian A, Eslami S, Jalili N, Farahi RH, Thundat T. Virtual resonance and frequency difference generation by van der Waals interaction. Phys Rev Lett 2011; 106:180801. [PMID: 21635079 DOI: 10.1103/physrevlett.106.180801] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Indexed: 05/30/2023]
Abstract
The ability to explore the interior of materials for the presence of inhomogeneities was recently demonstrated by mode synthesizing atomic force microscopy [L. Tetard, A. Passian, and T. Thundat, Nature Nanotech. 5, 105 (2009).]. Proposing a semiempirical nonlinear force, we show that difference frequency ω_ generation, regarded as the simplest synthesized mode, occurs optimally when the force is tuned to van der Waals form. From a parametric study of the probe-sample excitation, we show that the predicted ω_ oscillation agrees well with experiments. We then introduce the concept of virtual resonance to show that probe oscillations at ω_ can efficiently be enhanced.
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Affiliation(s)
- L Tetard
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123, USA
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20
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Zhu S, Lowndes DH, Budai J, Thundat T, Norton D, Warmack R. Morphology and Microstructure of (111) Crystalline CeO2 Films Grown on Amorphous SiO2 Substrates by Pulsed-Laser Ablation. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-354-603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe surface morphology and microstructure of (lll)-oriented CeO2 thin films, grown on amorphous fused silica (S1O2) substrates by low-energy-ion-beam assisted pulsed laser ablation, have been studied by atomic force microscopy (AFM) and x-ray diffraction (XRD). These CeO2 films are aligned with respect to a single in-plane axis despite being deposited on an amorphous substrate. There is a honeycomb-like growth morphology to the films and island-growth can be observed in thicker films. These islands, inside of which are high density of honeycomb-like clusters, are separated by a void network with ∼700nm width. However, on the surface of the thinnest film (∼3nm), only very small clusters (diameter <60nm) appear, and the boundaries of the void network are undefined, which implies that the film is just beginning to coalesce into clusters (grains). The combined AFM images and XRD pattern suggest these clusters probably are the initial seeds for the subsequent island growth. Based on these results, the growth mechanism of oriented CeO2 films on amorphous fused silica substrates is discussed.
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Abstract
ABSTRACTLarge 3D coherent islands are found to kinetically resist their further growth during post-deposition annealing of metastable 2D strained films. We reveal that a kinetic energy barrier exists to successive facet-layer growth of a 3D strained island at the expense of its surrounding 2D structure. The barrier increases with further growth of the island, which defines a self-limiting behavior of island growth. This self-limiting effect naturally explains a number of relevant features which have been observed experimentally including narrow island size distributions.
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Abstract
ABSTRACTIn order to understand Ge island nucleation and evolution, we have studied strain relaxation and clustering of Ge grown on Si(111) by molecular beam epitaxy (MBE) with in situ reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and Rutherford backscattering spectrometry (RBS). Our goal is to tailor the size and density of the nanocrystals by controlling thermodynamics and kinetics. At low temperature (∼ 450°C), we observe a sharp 2D-3D growth mode transition after 2.5ML ±0.1ML (we define a thickness of 1ML to be one-third the length of the body diagonal of the Ge conventional unit cell), when transmission diffraction features appear in RHEED and the surface lattice constant begins to relax. The mechanisms of island growth and strain relaxation change with growth temperature. At ∼ 700°C, transmission diffraction spots never appear in RHEED for Ge/Si(111) and strain relaxation occurs gradually. After 37ML of growth, the apparent in-plane lattice parameter increases only 1.5% over that of the Si substrate. This behavior is explained by the different manner in which islands initially nucleate and grow in the two temperature regimes. At low temperature, small islands nucleate and grow on a relatively rough wetting layer (which itself provides preferential sites for dislocation introduction). The areal density of the small islands is relatively high. At high temperature, a small number of islands grow very large from the outset. A general model indicates how, at low temperature, the relative difficulty of overcoming the barrier to dislocation formation actually results in an apparent larger degree of strain relief than at high temperature.
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Lowndes DH, Merkulov VI, Puretzky AA, Geohegan DB, Jellison GE, Rouleau CM, Thundat T. Amorphous Diamond Films Deposited by Pulsed-Laser Ablation: the Optimum Carbon-Ion Kinetic Energy and Effects of Laser Wavelength. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-526-325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractA systematic study has been made of changes in the bonding and optical properties of hydrogen-free tetrahedral amorphous carbon (ta-C) films, as a function of the kinetic energy of the incident carbon ions measured under film-deposition conditions. Ion probe measurements of the carbon ion kinetic energies produced by ArF and KrF laser ablation of graphite are compared under identical beam-focusing conditions. Much higher C+ kinetic energies are produced by ArF-laser ablation than by KrF for any given fluence and spot size. Electron energy loss spectroscopy and scanning ellipsometry measurements of the sp3 bonding fraction, plasmon energy, and optical properties reveal a well-defined optimum kinetic energy of 90 eV to deposit ta-C films having the largest sp3 fraction and the widest optical (Tauc) energy gap (equivalent to minimum near-gap optical absorption). Tapping-mode atomic force microscope measurements show that films deposited at near-optimum kinetic energy are extremely smooth, with rms roughness of only ~ 1 Å over distances of several hundred nm, and are relatively free of particulates.
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Muralidharan G, Wig A, Pinnaduwage LA, Hedden DL, Datskos PG, Thundat T, Lareau RT. Chemical Sensing With Resistive Microcantilevers. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-723-o6.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractMEMS-based microcantilevers have been proposed for a variety of biological and chemical sensing applications. Measuring the magnitude of microcantilever deflection due to adsorption-induced bending, and following the variation in the resonant frequency of the microcantilevers due to the adsorbed mass are two techniques commonly employed for sensing analytes. Apart from possessing a high level of sensitivity to small changes in mass, microcantilevers are also very sensitive to small changes in temperature and hence the flow of heat. One way of achieving high sensitivity in thermal measurements is by using a bimaterial microcantilever and measuring its deflection as a result of thermal fluctuations. Commercially available piezoresistive microcantilevers are an example of bimaterial cantilevers and in this study, we propose the use of such cantilevers for sensing explosives. We show that sensing can be accomplished by following the differences in the thermal response of the cantilevers introduced by the presence of explosives adsorbed from the vapor phase onto the surface of the cantilever. We discuss the issues involved in determining the sensitivity of detection and selectivity of detection.
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Tetard L, Passian A, Farahi R, Thundat T. Atomic force microscopy of silica nanoparticles and carbon nanohorns in macrophages and red blood cells. Ultramicroscopy 2010; 110:586-91. [DOI: 10.1016/j.ultramic.2010.02.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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26
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Tetard L, Passian A, Thundat T. New modes for subsurface atomic force microscopy through nanomechanical coupling. Nat Nanotechnol 2010; 5:105-109. [PMID: 20023642 DOI: 10.1038/nnano.2009.454] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 11/19/2009] [Indexed: 05/28/2023]
Abstract
Non-destructive, nanoscale characterization techniques are needed to understand both synthetic and biological materials. The atomic force microscope uses a force-sensing cantilever with a sharp tip to measure the topography and other properties of surfaces. As the tip is scanned over the surface it experiences attractive and repulsive forces that depend on the chemical and mechanical properties of the sample. Here we show that an atomic force microscope can obtain a range of surface and subsurface information by making use of the nonlinear nanomechanical coupling between the probe and the sample. This technique, which is called mode-synthesizing atomic force microscopy, relies on multi-harmonic forcing of the sample and the probe. A rich spectrum of first- and higher-order couplings is discovered, providing a multitude of new operational modes for force microscopy, and the capabilities of the technique are demonstrated by examining nanofabricated samples and plant cells.
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Affiliation(s)
- L Tetard
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123, USA
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Affiliation(s)
- C. W. Van Neste
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996
| | - L. R. Senesac
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996
| | - T. Thundat
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996
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28
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Yi D, Passian A, Lereu AL, Thundat T. An experimental investigation of analog delay generation for dynamic control of microsensors and atomic force microscopy. Ultramicroscopy 2007; 107:1020-6. [PMID: 17576037 DOI: 10.1016/j.ultramic.2007.03.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 03/19/2007] [Indexed: 11/19/2022]
Abstract
We present an implementation of pure-time-delay generation in analog signals located in the kilo-Hertz frequency band. The controlled constant delays that are produced engage in a feedback system to investigate the dynamic response of microcantilevers. Delayed systems offer a vast richness of eigenvalues resulting in the possibility of excitations at frequencies other than that of the fundamental mode. Different cantilever actuation and delay generation approaches are investigated and compared, and detailed experimental observation of the dynamic response of the system is presented. Based on our results, an acoustic excitation is devised that may be used as an efficient sensor.
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Affiliation(s)
- D Yi
- Oak Ridge National Laboratory, Bldg. 4500 S, MS 6123, Bethel Valley Road, Oak Ridge, TN 37831-6123, USA
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29
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Passian A, Zahrai S, Lereu AL, Farahi RH, Ferrell TL, Thundat T. Nonradiative surface plasmon assisted microscale Marangoni forces. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:066311. [PMID: 16906980 DOI: 10.1103/physreve.73.066311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 05/03/2006] [Indexed: 05/11/2023]
Abstract
When a liquid droplet experiences a temperature inhomogeneity along its bounding surface, a surface energy gradient is engendered, which when, in a continuous sense, exceeding a threshold, results in a convective flow dissipating the energy. If the associated temperature gradients are sustained by the interface between the liquid and a supporting substrate, the induced flow can result in the lateral motion of the droplet overcoming the viscosity and inertia. Recently, pico-liter adsorbed and applied droplets were shown experimentally to be transported, and divided by the decay of optically excited surface plasmons into phonons in a thin gold foil. The decaying events locally modify the temperature of the liquid-solid interface, establishing microscale thermal gradients of sufficient magnitude for the droplet to undergo thermocapillary flow. We present experimental evidence of such gradients resulting in local surface modification associated with the excitation of surface plasmons. We show theoretically that the observed effect is due to Marangoni forces, and computationally visualize the flow characteristics for the experimental parameters. As an application based on our results, we propose a method for an all-optical modulation of light by light mediated by the droplet oscillations. Furthermore, the results have important consequences for microfluidics, droplet actuation, and simultaneous surface plasmon resonance sensing and spectroscopy.
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Affiliation(s)
- A Passian
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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30
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Farahi RH, Passian A, Zahrai S, Lereu AL, Ferrell TL, Thundat T. Microscale Marangoni actuation: All-optical and all-electrical methods. Ultramicroscopy 2006; 106:815-21. [PMID: 16765516 DOI: 10.1016/j.ultramic.2005.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 12/11/2005] [Indexed: 10/24/2022]
Abstract
We present experimental results from an all-optical microfluidic platform that may be complimented by a thin film all-electrical network. Using these configurations we have studied the microfluidic convective flow systems of silicone oil, glycerol, and 1,3,5-trinitrotoluene on open surfaces through the production of surface tension gradients derived from thermal gradients. We show that sufficient localized thermal variation can be created utilizing surface plasmons and/or engaging individually addressable resistive thermal elements. Both studies manipulate fluids via Marangoni forces, each having their unique exploitable advantages. Surface plasmon excitation in metal foils are the driving engine of many physical-, chemical-, and bio-sensing applications. Incorporating, for the first time, the plasmon concept in microfluidics, our results thus demonstrate great potential for simultaneous fluid actuation and sensing.
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Affiliation(s)
- R H Farahi
- Oak Ridge National Laboratory, Bethel Valley Rd., Bldg. 4500 S, MS 6123, TN 37831, USA
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31
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Kalinin SV, Rodriguez BJ, Shin J, Jesse S, Grichko V, Thundat T, Baddorf AP, Gruverman A. Bioelectromechanical imaging by scanning probe microscopy: Galvani's experiment at the nanoscale. Ultramicroscopy 2006; 106:334-40. [PMID: 16387441 DOI: 10.1016/j.ultramic.2005.10.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 10/25/2005] [Accepted: 10/26/2005] [Indexed: 11/25/2022]
Abstract
Since the discovery in the late 18th century of electrically induced mechanical response in muscle tissue, coupling between electrical and mechanical phenomena has been shown to be a near-universal feature of biological systems. Here, we employ scanning probe microscopy (SPM) to measure the sub-Angstrom mechanical response of a biological system induced by an electric bias applied to a conductive SPM tip. Visualization of the spiral shape and orientation of protein fibrils with 5 nm spatial resolution in a human tooth and chitin molecular bundle orientation in a butterfly wing is demonstrated. In particular, the applicability of SPM-based techniques for the determination of molecular orientation is discussed.
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Affiliation(s)
- Sergei V Kalinin
- Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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32
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Chaudhury A, Hesketh P, Hu Z, Thundat T. Design and Fabrication of Piezoresistive Microcantilever Array for Stress-based Biochemical Detection. Meet Abstr 2006; MA2005-02:1291-1291. [DOI: 10.1149/ma2005-02/37/1291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
Abstract not Available.
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33
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Rodriguez BJ, Kalinin SV, Shin J, Jesse S, Grichko V, Thundat T, Baddorf AP, Gruverman A. Electromechanical imaging of biomaterials by scanning probe microscopy. J Struct Biol 2006; 153:151-9. [PMID: 16403652 DOI: 10.1016/j.jsb.2005.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2005] [Revised: 09/23/2005] [Accepted: 10/04/2005] [Indexed: 10/25/2022]
Abstract
The majority of calcified and connective tissues possess complex hierarchical structure spanning the length scales from nanometers to millimeters. Understanding the biological functionality of these materials requires reliable methods for structural imaging on the nanoscale. Here, we demonstrate an approach for electromechanical imaging of the structure of biological samples on the length scales from tens of microns to nanometers using piezoresponse force microscopy (PFM), which utilizes the intrinsic piezoelectricity of biopolymers such as proteins and polysaccharides as the basis for high-resolution imaging. Nanostructural imaging of a variety of protein-based materials, including tooth, antler, and cartilage, is demonstrated. Visualization of protein fibrils with sub-10nm spatial resolution in a human tooth is achieved. Given the near-ubiquitous presence of piezoelectricity in biological systems, PFM is suggested as a versatile tool for micro- and nanostructural imaging in both connective and calcified tissues.
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Affiliation(s)
- B J Rodriguez
- Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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34
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Abstract
We present optical microfluidic manipulation of silicone oil and glycerol via surface tension driven forces sustained by surface plasmon deexcitation energy. The phonon energy associated with the decaying optically excited surface plasmons in a thin gold foil creates thermal gradients capable of actuating fluid flows. Spectral dependence of the plasmon decay length and control of optical beam characteristics are shown to provide a means for further manipulation.
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Affiliation(s)
- R H Farahi
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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35
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Boiadjiev VI, Brown GM, Pinnaduwage LA, Goretzki G, Bonnesen PV, Thundat T. Photochemical hydrosilylation of 11-undecenyltriethylammonium bromide with hydrogen-terminated Si surfaces for the development of robust microcantilever sensors for Cr(VI). Langmuir 2005; 21:1139-1142. [PMID: 15697249 DOI: 10.1021/la047852n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report a novel approach to the design and development of microcantilever sensors in which photochemical hydrosilylation is used to modify the microcantilever surface. This process enables individual microcantilevers in multicantilever array chips to be modified separately by focusing the activating UV light sequentially on each particular cantilever. Photochemical hydrosilylation of 11-undecenyltriethylammonium bromide with hydrogen-terminated silicon microcantilever surfaces was carried out to yield a robust quaternary ammonium terminated organic monolayer suitable for chromate detection. The surface functionalities retain their affinity toward Cr(VI), and the organic monolayer is dense enough to generate significant surface stress upon subsequent adsorption of chromate ions from aqueous solutions.
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36
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Passian A, Lereu AL, Arakawa ET, Wig A, Thundat T, Ferrell TL. Modulation of multiple photon energies by use of surface plasmons. Opt Lett 2005; 30:41-43. [PMID: 15648631 DOI: 10.1364/ol.30.000041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A form of optical modulation at low pulse rates is reported in the case of surface plasmons excited by 1.55-microm photons in a thin gold foil. Several visible-photon energies are shown to be pulsed by the action of the infrared pulses, the effect being maximized when each visible beam also excites surface plasmons. The infrared surface plasmons are implicated as the primary cause of thermally induced changes in the foil. The thermal effects dissipate in sufficiently small times so that operation up to the kilohertz range in pulse repetition frequency is obtained. Unlike direct photothermal phenomena, no phase change is necessary for the effect to be observed.
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Affiliation(s)
- A Passian
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200, USA.
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37
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Tian F, Pei JH, Hedden DL, Brown GM, Thundat T. Observation of the surface stress induced in microcantilevers by electrochemical redox processes. Ultramicroscopy 2004; 100:217-23. [PMID: 15231313 DOI: 10.1016/j.ultramic.2003.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2003] [Revised: 11/24/2003] [Accepted: 12/02/2003] [Indexed: 10/26/2022]
Abstract
The potential-induced surface stress of a solid electrode was investigated in an electrochemical cell. Gold-coated atomic force microscopy microcantilevers were used as working electrodes to measure the current-potential response (by cyclic voltammetry) and simultaneous bending characteristics in solutions of NaNO3 and K3Fe(CN)6/NaNO3. The observed changes of differential surface stress at a microcantilever electrode were attributed to electrochemical-potential-induced changes in surface charge density, ion adsorption/desorption, and electron transfer across the electrode surface. The potential dependent change in stress shows promise for the study of microscopic properties at the solid-electrolyte interface.
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Affiliation(s)
- F Tian
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6123, USA
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38
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Passian A, Wig A, Lereu AL, Evans PG, Meriaudeau F, Thundat T, Ferrell TL. Probing large area surface plasmon interference in thin metal films using photon scanning tunneling microscopy. Ultramicroscopy 2004; 100:429-36. [PMID: 15231335 DOI: 10.1016/j.ultramic.2003.11.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 10/26/2003] [Accepted: 11/18/2003] [Indexed: 11/24/2022]
Abstract
The interference of surface plasmons can provide important information regarding the surface features of the hosting thin metal film. We present an investigation of the interference of optically excited surface plasmons in the Kretschmann configuration in the visible spectrum. Large area surface plasmon interference regions are generated at several wavelengths and imaged with the photon scanning tunneling microscope. Furthermore, we discuss the non-retarded dispersion relations for the surface plasmons in the probe-metal system modeled as confocal hyperboloids of revolution in the spheroidal coordinate systems.
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Affiliation(s)
- A Passian
- Oak Ridge National Laboratory, Oak Ridge, Bethel Valley Rd., Bldg. 4500 S, MS 6123, TN 37831-6219, USA.
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39
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Pinnaduwage LA, Thundat T, Gehl A, Wilson SD, Hedden DL, Lareau RT. Desorption characteristics of uncoated silicon microcantilever surfaces for explosive and common nonexplosive vapors. Ultramicroscopy 2004; 100:211-6. [PMID: 15231312 DOI: 10.1016/j.ultramic.2003.11.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2003] [Revised: 11/18/2003] [Accepted: 11/18/2003] [Indexed: 11/29/2022]
Abstract
We measured the desorption of explosive trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5-triazine (RDX) vapors from piezoresistive silicon microcantilevers under ambient air. Depending on the amount of vapor loaded on the cantilever, TNT desorption took a few minutes to tens of minutes (for nanogram quantities). On the other hand, no significant loss of PETN or RDX was observed after many hours. We also measured desorption of common "nonexplosive" compounds (water, acetone, and ethyl alcohol) and observed that desorption was too fast to be measured. There is a good correlation between the desorption time and the melting point (or the vapor pressure) of a particular substance. In principle, this method can be used to measure desorption rates of various substances from cantilever surfaces.
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Affiliation(s)
- L A Pinnaduwage
- Department of Physics, University of Tennessee, Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge, TN 37831-6123, Knoxville, TN 37996, USA.
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40
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Pinnaduwage LA, Yi D, Tian F, Thundat T, Lareau RT. Adsorption of trinitrotoluene on uncoated silicon microcantilever surfaces. Langmuir 2004; 20:2690-2694. [PMID: 15835138 DOI: 10.1021/la035658f] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We measured the adsorption characteristics of trinitrotoluene (TNT) on piezoresistive silicon microcantilever surfaces under ambient air using a well-characterized TNT vapor generator. This allowed us to quantify the adsorption parameters and to estimate the sticking coefficient. The sticking coefficient initially increases with TNT exposure time and then levels off around 0.3. Atomic force microscopy images of silicon surfaces exposed to TNT revealed "island" formation of the adsorbate on the silicon surface. At low exposure times, mainly the number density of islands increased with exposure time; at longer exposure times, the size (in particular, height) of the islands grew, corresponding to the higher sticking coefficients. These observations can be qualitatively explained via the difference between TNT-surface and TNT-TNT interactions mediated by water molecules.
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Affiliation(s)
- L A Pinnaduwage
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6122, USA
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41
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Pinnaduwage LA, Boiadjiev VI, Brown GM, Thundat T, Petersen SW. Detection of Hexavalent Chromium in Ground Water Using a Single Microcantilever Sensor. ACTA ACUST UNITED AC 2004. [DOI: 10.1166/sl.2004.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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42
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Abstract
Experimental observation of self-sustaining oscillations via a delayed feedback system is presented for a rectangular silicon microcantilever. The system is modeled as one and two-dimensional damped oscillator and the resulting delay differential equations are studied in frequency and time domain. The shortcomings of each model are outlined, and an improved formulation of the dynamics of the cantilever is presented.
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Affiliation(s)
- A Passian
- Oak Ridge National Laboratory, Bethel Valley Road, Bldg 4500 S MS 6123, Oak Ridge, TN 37831, USA.
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43
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Abstract
The Knudsen effect is estimated theoretically and observed experimentally using a U-shaped silicon microcantilever. Though Knudsen forces are extremely small in most cases involving microcantilevers, there exist situations where these forces can be significant and may be important in atomic force microscopy and in microelectromechanical systems (MEMS). The criteria for the presence of Knudsen forces are outlined and an analytical expression in the form of a linear function of the pressure is given for the force in the free molecular regime. The experimental results display peaks in the transitional regime while varying linearly in the molecular regime.
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Affiliation(s)
- A Passian
- Oak Ridge National Laboratory, Bethel Valley Road, Building 4500 S MS 6123, Oak Ridge, TN 37831-6123, USA.
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44
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Muralidharan G, Wig A, Pinnaduwage LA, Hedden D, Thundat T, Lareau RT. Adsorption-desorption characteristics of explosive vapors investigated with microcantilevers. Ultramicroscopy 2003; 97:433-9. [PMID: 12801699 DOI: 10.1016/s0304-3991(03)00071-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Understanding the kinetics of adsorption and desorption of explosive vapors such as TNT from surfaces is important in the design of sensors. We report for the first time, the adsorption-desorption characteristics of TNT from a Si-microcantilever exposed to vapors of TNT. It was observed that TNT readily sticks to the exposed Si surface with the adsorption kinetics showing an initial exponential behavior followed by roughly linear kinetics. It was also observed that for cantilever temperatures close to room temperature, TNT desorbs spontaneously from the surface with decaying exponential kinetics. Based on the known equilibrium partial vapor pressures of TNT, the "effective" sticking coefficient for the silicon oxide surface at room temperature under the experimental conditions was calculated to be about 0.02. This information can be very useful in the design of sensors and that of vapor-delivery systems.
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Affiliation(s)
- G Muralidharan
- Oak Ridge National Laboratory, Life Sciences Division, Oak Ridge, TN 37831 6123, USA
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45
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Pinnaduwage LA, Gehl A, Hedden DL, Muralidharan G, Thundat T, Lareau RT, Sulchek T, Manning L, Rogers B, Jones M, Adams JD. A microsensor for trinitrotoluene vapour. Nature 2003; 425:474. [PMID: 14523436 DOI: 10.1038/425474a] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L A Pinnaduwage
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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46
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Kumar P, Mehta A, Dadmun MD, Zheng J, Peyser L, Bartko AP, Dickson RM, Thundat T, Sumpter BG, Noid DW, Barnes MD. Narrow-Bandwidth Spontaneous Luminescence from Oriented Semiconducting Polymer Nanostructures. J Phys Chem B 2003. [DOI: 10.1021/jp034107v] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P. Kumar
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - A. Mehta
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - M. D. Dadmun
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - J. Zheng
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - L. Peyser
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - A. P. Bartko
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - R. M. Dickson
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - T. Thundat
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - B. G. Sumpter
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - D. W. Noid
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
| | - M. D. Barnes
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37830, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142, and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6142
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47
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Passian A, Warmack RJ, Ferrell TL, Thundat T. Thermal transpiration at the microscale: a Crookes cantilever. Phys Rev Lett 2003; 90:124503. [PMID: 12688878 DOI: 10.1103/physrevlett.90.124503] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2002] [Indexed: 05/24/2023]
Abstract
Local temperature inhomogeneities in systems containing micron and submicron objects can result in unexpected consequences. If the mean free path of the host gas constituents is comparable to a characteristic length of the system, then a net exchange of momentum occurs between the constituents and the involved surfaces. For a given temperature gradient and a given pressure range, this results in the presence of Knudsen and Knudsen-like forces (KF). The pressure dependence of these forces has been studied using a microelectromechanical system composed of a microcantilever near a substrate surface. Nano-Newton scale KF are observed by the bending of the microcantilever as monitored by the charge variation on the microcantilever-substrate assembly in a capacitive mode.
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Affiliation(s)
- A Passian
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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48
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Abstract
Microfabricated cantilever beams promise to bring about a revolution in the field of chemical, physical, and biological sensor development. The resonance frequency of a microfabricated cantilever shifts sensitively because of mass loading from molecular adsorption. The minimum detectable adsorbed mass on a cantilever sensor can be increased by orders of magnitude by changing the dimensions of the device; smaller and thicker cantilevers offer higher resonance frequency and therefore better mass detection sensitivity. Here we describe micromachined silicon cantilevers that are 0.5 to 4 microns in length, fabricated with the use of a focused ion beam (FIB). In addition, we demonstrate a technique for detection of the cantilever resonance frequency that is based on electron transfer.
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Affiliation(s)
- P G Datskos
- Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Bartko AP, Peyser LA, Dickson RM, Mehta A, Thundat T, Bhargava R, Barnes M. Observation of dipolar emission patterns from isolated Eu3+:Y2O3 doped nanocrystals: new evidence for single ion luminescence. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)00630-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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