Nanocantilevers with Adjustable Static Deflection and Significantly Tunable Spectrum Resonant Frequencies for Applications in Nanomechanical Mass Sensors

Stachiv, Ivo; Šittner, Petr

doi:10.3390/nano8020116

Cited by 21 publications

(15 citation statements)

References 56 publications

(81 reference statements)

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“…To begin, we recall a known fact that once a thin layer film is sputtered on an elastic substrate, it generates in-plane stresses and also alters the overall cantilever resonator elastic properties, particularly in near vicinity of its clamped end [6,[30][31][32][33]. These effects, that originate from mismatches in strains and the coefficient of thermal expansion between substrate and film, have been proven to notably affect the resonant frequencies of ultrathin cantilever resonators (i.e., thin sheets) [32,33].…”

Section: Flexural Oscillations Of Two-layered (Multi-layered) Microcamentioning

confidence: 99%

“…Functional micro-/nanostructures made of substrate and one or multiple ultrathin films are widely used in applications like photovoltaics [1], micro-electronics [2], optics [3,4], tunable resonators [5,6], and various sensors [7][8][9][10][11][12]. Preparation of these structures involves repeated usage of multiple fabrication processes such as deposition, lithography, etching, and cleaning.…”

Section: Introductionmentioning

confidence: 99%

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Simple Non-Destructive Method of Ultrathin Film Material Properties and Generated Internal Stress Determination Using Microcantilevers Immersed in Air

Stachiv

Gan

2019

Coatings

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Recent progress in nanotechnology has enabled to design the advanced functional micro-/nanostructures utilizing the unique properties of ultrathin films. To ensure these structures can reach the expected functionality, it is necessary to know the density, generated internal stress and the material properties of prepared films. Since these films have thicknesses of several tens of nm, their material properties, including density, significantly deviate from the known bulk values. As such, determination of ultrathin film material properties requires usage of highly sophisticated devices that are often expensive, difficult to operate, and time consuming. Here, we demonstrate the extraordinary capability of a microcantilever commonly used in a conventional atomic force microscope to simultaneously measure multiple material properties and internal stress of ultrathin films. This procedure is based on detecting changes in the static deflection, flexural and torsional resonant frequencies, and the corresponding quality factors of the microcantilever vibrating in air before and after film deposition. In contrast to a microcantilever in vacuum, where the quality factor depends on the combination of multiple different mechanical energy losses, in air the quality factor is dominated just by known air damping, which can be precisely controlled by changing the air pressure. Easily accessible expressions required to calculate the ultrathin film density, the Poisson’s ratio, and the Young’s and shear moduli from measured changes in the microcantilever resonant frequencies, and quality factors are derived. We also show that the impact of uncertainties on determined material properties is only minor. The validity and potential of the present procedure in material testing is demonstrated by (i) extracting the Young’s modulus of atomic-layer-deposited TiO2 films coated on a SU-8 microcantilever from observed changes in frequency response and without requirement of knowing the film density, and (ii) comparing the shear modulus and density of Si3N4 films coated on the silicon microcantilever obtained numerically and by present method.

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Section: Flexural Oscillations Of Two-layered (Multi-layered) Microcamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simple Non-Destructive Method of Ultrathin Film Material Properties and Generated Internal Stress Determination Using Microcantilevers Immersed in Air

Stachiv

Gan

2019

Coatings

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“…The SMA (NiTi) film generates the interlayer in-plane stress over the entire resonator surface [29,30]. This stress is either tensile or compressive depending on the resonator dimensions and material properties, preparation processes and the final resonator configuration [31].…”

Section: Theorymentioning

confidence: 99%

“…These actuators are, therefore, with a relatively low actuating speed of a few kHz [28] caused by the necessity of cooling the SMA components. Recently, hybrid SMA-based nanomechanical resonators made of an elastic substrate and NiTi in form of thin film were proposed [29,30]. These hybrid resonators were proven to operate at high resonant frequency ranges (i.e., up to tens of MHz) that can be significantly tuned up and down making them suitable for applications, such as radio frequency filters, infrared and temperature sensors.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Shape Memory Alloy-Based Nanomechanical Resonators for Ultrathin Film Elastic Properties Determination and Heavy Mass Spectrometry

Stachiv

Gan

2019

Materials

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Micro-/nanomechanical resonators are often used in material science to measure the elastic properties of ultrathin films or mass spectrometry to estimate the mass of various chemical and biological molecules. Measurements with these sensors utilize changes in the resonant frequency of the resonator exposed to an investigated quantity. Their sensitivities are, therefore, determined by the resonant frequency. The higher resonant frequency and, correspondingly, higher quality factor (Q-factor) yield higher sensitivity. In solution, the resonant frequency (Q-factor) decreases causing a significant lowering of the achievable sensitivity. Hence, the nanomechanical resonator-based sensors mainly operate in a vacuum. Identification by nanomechanical resonator also requires an additional reference measurement on the identical unloaded resonator making experiments, due to limiting achievable accuracies in current nanofabrication processes, yet challenging. In addition, the mass spectrometry by nanomechanical resonator can be routinely performed for light analytes (i.e., analyte is modelled as a point particle). For heavy analytes such as bacteria clumps neglecting their stiffness result in a significant underestimation of determined mass values. In this work, we demonstrate the extraordinary capability of hybrid shape memory alloy (SMA)-based nanomechanical resonators to i) notably tune the resonant frequencies and improve Q-factor of the resonator immersed in fluid, ii) determine the Young’s (shear) modulus of prepared ultrathin film only from frequency response of the resonator with sputtered film, and iii) perform heavy analyte mass spectrometry by monitoring shift in frequency of just a single vibrational mode. The procedures required to estimate the Young’s (shear) modulus of ultrathin film and the heavy analyte mass from observed changes in the resonant frequency caused by a phase transformation in SMA are developed and, afterward, validated using numerical simulations. The present results demonstrate the outstanding potential and capability of high frequency operating hybrid SMA-based nanomechanical resonators in sensing applications that can be rarely achieved by current nanomechanical resonator-based sensors.

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“…Here, in contrast to the usual thermally actuated SMA, the high frequency actuation is generated by the elastic substrate material. Furthermore, Stachiv et al [17] also proposed nanocantilevers with a tunable spectrum of the resonant frequencies and changeable static deflection utilizing the phase transformation of NiTi film sputtered on the elastic substrate material.…”

Section: Introductionmentioning

confidence: 99%

Optimal Design of Shape Memory Alloy Composite under Deflection Constraint

2019

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Shape-adaptive or morphing capability in both aerospace structures and wind turbine blade design is regarded as significant to increase aerodynamic performance and simplify mechanisms by reducing the number of moving parts. The underlying bistable behavior of asymmetric cross-ply composites makes them a suitable candidate for morphing applications. To date, various theoretical and experiential studies have been carried out to understand and predict the bistable behavior of asymmetric laminates and especially the curvature obtained in their stable configurations. However, when the bi-stable composite plate is integrated with shape memory alloy wires to control the curvature and to snap from a stable configuration to the other (shape memory alloy composite, SMAC), the identification of the design parameters, namely laminate edge length, ply thickness and ply orientation, is not straightforward. The aim of this article is to present the formulation of an optimization problem for the parameters of an asymmetric composite laminate integrated with pre-stressed shape memory alloys (SMA) wires under bi-stability and a minimum deflection requirement. Wires are modeled as an additional ply placed at the mid-plane of the composite host plate. The optimization problem is solved numerically in MATLAB and optimal design variables are then used to model the SMAC in ABAQUS™. Finite element results are compared against numerical results for validation.

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Nanocantilevers with Adjustable Static Deflection and Significantly Tunable Spectrum Resonant Frequencies for Applications in Nanomechanical Mass Sensors

Cited by 21 publications

References 56 publications

Simple Non-Destructive Method of Ultrathin Film Material Properties and Generated Internal Stress Determination Using Microcantilevers Immersed in Air

Simple Non-Destructive Method of Ultrathin Film Material Properties and Generated Internal Stress Determination Using Microcantilevers Immersed in Air

Hybrid Shape Memory Alloy-Based Nanomechanical Resonators for Ultrathin Film Elastic Properties Determination and Heavy Mass Spectrometry

Optimal Design of Shape Memory Alloy Composite under Deflection Constraint

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