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Search for "quality factor" in Full Text gives 119 result(s) in Beilstein Journal of Nanotechnology.

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

  • Kai Braun,
  • Xiao Wang,
  • Andreas M. Kern,
  • Hilmar Adler,
  • Heiko Peisert,
  • Thomas Chassé,
  • Dai Zhang and
  • Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

Graphical Abstract
  • scattered to the far field. While the gap modes plasmon resonance is very broad, exhibiting a quality factor of only Q ≈ 15, the resonantly stored energy in the optical near field in the gap is extremely well localized, in a volume having an upper limit of approximately 4 × 4 × 1 nm3 (see Figure S8
  • Information File 1) of the junction, Γ = (ω0/Q) its spectral bandwidth, Q its quality factor and Vm its spatial volume. The total emission rate γem comprises all optical emission processes in the gap, i.e., spontaneous and stimulated recombination as well as Raman scattering (ΦLσR). From the measured Raman
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Published 04 May 2015

Optimization of phase contrast in bimodal amplitude modulation AFM

  • Mehrnoosh Damircheli,
  • Amir F. Payam and
  • Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 1072–1081, doi:10.3762/bjnano.6.108

Graphical Abstract
  • be described by the system of two differential modal equations, with i = 1,2; ωi, ki, Qi, , Ai and A0i are, respectively, the angular frequency, the force constant, quality factor, phase shift, amplitude and free amplitude of mode i; m = 0.25mc is an effective mass while mc is the real cantilever–tip
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Published 28 Apr 2015

Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

  • Mykola Telychko,
  • Jan Berger,
  • Zsolt Majzik,
  • Pavel Jelínek and
  • Martin Švec

Beilstein J. Nanotechnol. 2015, 6, 901–906, doi:10.3762/bjnano.6.93

Graphical Abstract
  • custom-built quartz-tuning fork sensor was used for the measurements. It had a main resonance frequency of 51294 Hz, a quality factor above 1000 and an estimated stiffness of ≈3800 N·m−1 [22]. The contact to the tungsten tip was made of a thin golden wire in order to avoid crosstalk with the deflection
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Published 07 Apr 2015

Stick–slip behaviour on Au(111) with adsorption of copper and sulfate

  • Nikolay Podgaynyy,
  • Sabine Wezisla,
  • Christoph Molls,
  • Shahid Iqbal and
  • Helmut Baltruschat

Beilstein J. Nanotechnol. 2015, 6, 820–830, doi:10.3762/bjnano.6.85

Graphical Abstract
  • quality factor of the cantilever. All AFM measurements were performed at room temperature. Friction force maps shown here are the difference images between both scan directions. Due to the relatively high load used in our experiments, the tip radius quickly approached a value of around 100 nm, but then
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Published 26 Mar 2015

Capillary and van der Waals interactions on CaF2 crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

  • Annalisa Calò,
  • Oriol Vidal Robles,
  • Sergio Santos and
  • Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

Graphical Abstract
  • vs zc curves in the repulsive region till a flat plateau was obtained [34]. The resonance frequency, spring constant and quality factor (Q ≈ 400) of the cantilever were calibrated in situ at a distance smaller than 200 nm from the surface. The resonance frequency was found to decrease approximately
  • relative to the drive force, and Q is the quality factor due to dissipation with the medium. The experimental APD curves cover the approach and the retract part during one cycle, with a drift smaller than 0.5 nm (see Supporting Information File 1, Figure S1). Only approach curves for which the cantilever
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Published 25 Mar 2015

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

  • M. Kalyan Phani,
  • Anish Kumar,
  • T. Jayakumar,
  • Walter Arnold and
  • Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

Graphical Abstract
  • micrometer resolution. An improved UAFM technique was used for mapping the resonance frequency and the quality factor, Q, in carbon reinforced plastics composites [7]. In recent years, AFAM has been extensively used to determine elastic stiffness or damping properties in nano-crystalline nickel [2], PMMA
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Published 18 Mar 2015

Influence of spurious resonances on the interaction force in dynamic AFM

  • Luca Costa and
  • Mario S. Rodrigues

Beilstein J. Nanotechnol. 2015, 6, 420–427, doi:10.3762/bjnano.6.42

Graphical Abstract
  • frequency different from the natural frequency is accounted for only through a rescaling of the effective mass and quality factor. Whereas, if a and are calibrated, the cantilever spring constant is not fixed to any value. The reasoning above assumes that the measurement corresponds to the position of the
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Published 10 Feb 2015

Dynamic force microscopy simulator (dForce): A tool for planning and understanding tapping and bimodal AFM experiments

  • Horacio V. Guzman,
  • Pablo D. Garcia and
  • Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 369–379, doi:10.3762/bjnano.6.36

Graphical Abstract
  • mass of the cantilever tip, ω0 is the angular resonant frequency, Q the quality factor, k the spring constant of the fundamental resonance (first flexural mode) and Fts is the tip–sample interaction force. The above equation is applicable when the contributions from higher modes to the cantilever
  • ) cosh (κn) = 0, where κn is the nth positive real root of the above equation and mc is the real mass of the cantilever. Additionally, the quality factor is defined as where Tip–sample interaction forces The simulator includes a variety of models and tip–surface force interactions. The interactions are
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Published 04 Feb 2015

High-frequency multimodal atomic force microscopy

  • Adrian P. Nievergelt,
  • Jonathan D. Adams,
  • Pascal D. Odermatt and
  • Georg E. Fantner

Beilstein J. Nanotechnol. 2014, 5, 2459–2467, doi:10.3762/bjnano.5.255

Graphical Abstract
  • of the cantilever (P0) as where V0 is the excitation voltage, f0 the excitation frequency, k the spring constant, A the amplitude and Q the quality factor far from the surface [39]. The acquired dissipation is, to a first approximation, only dependent on the materials properties and the additional
  • and inversely with the quality factor. The increased ratio of resonance frequency to spring constant makes it clear that the use of small cantilevers is ideally suited for low-dissipation imaging on multiple dynamic modes. Drive amplitude modulation imaging For biophysical imaging with atomic force
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Published 22 Dec 2014

Dissipation signals due to lateral tip oscillations in FM-AFM

  • Michael Klocke and
  • Dietrich E. Wolf

Beilstein J. Nanotechnol. 2014, 5, 2048–2057, doi:10.3762/bjnano.5.213

Graphical Abstract
  • quality factor Q = (mxωx)/γ, where . We only consider damping in the lateral degree of freedom and therefore omit any sort of indexing of damping parameters (such as Qx). It should be clear that if the damping in the z-direction is explicitly used, one will have to distinguish between Qx and Qz. Without
  • oscillating (see e.g. [35]). Then, however, in order to compare with experiments, it is important to show robustness of the simulation results with respect to variations of kz. The sensitivity with respect to all parameters (including the lateral quality factor Q) will be assessed in the later sections
  • limited to very narrow ranges of frequency ratios. Quality factor We studied the influence of the quality factor on the energy dissipation rate (Figure 6). For high Q-values, the trajectory of the tip in the strong interaction region is nearly unaffected by the damping in the lateral degree of freedom
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Published 10 Nov 2014

Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

  • Matthew F. B. Green,
  • Taner Esat,
  • Christian Wagner,
  • Philipp Leinen,
  • Alexander Grötsch,
  • F. Stefan Tautz and
  • Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 1926–1932, doi:10.3762/bjnano.5.203

Graphical Abstract
  • quality factor of Q ≈ 70,000. Contacting and manipulation were performed with the qPlus sensor oscillating with an amplitude of A0 ≈ 0.2–0.3 Å. Interactions in the junction were monitored by measuring the frequency shift Δf(z) ≈ −(f0/2k0)dFz/dz, where k0 = 1800 N/m is the stiffness of the quartz tuning
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Published 31 Oct 2014

Dynamic calibration of higher eigenmode parameters of a cantilever in atomic force microscopy by using tip–surface interactions

  • Stanislav S. Borysov,
  • Daniel Forchheimer and
  • David B. Haviland

Beilstein J. Nanotechnol. 2014, 5, 1899–1904, doi:10.3762/bjnano.5.200

Graphical Abstract
  • lever inverse responsivity, Vn is the measured voltage (corresponding to the eigencoordinate zn = αnVn, where total tip deflection is ), is the linear transfer function of a harmonic oscillator with the resonant frequency ωn and quality factor Qn, F is a nonlinear tip–surface force and fn is a drive
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Published 29 Oct 2014
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  • the sample storage and loss moduli. Similarly, in contact resonance methods [4][5][6][7][8] the user generally measures the cantilever frequency response to small amplitude excitations, from which an effective resonance frequency and quality factor can be computed and post-processed to also give the
  • in contact mode by using a band of frequencies such that the Fourier transform of the tip response can be fit to a Lorentzian curve that readily yields the effective resonance frequency and quality factor, which in turn yield the desired moduli. A third method that provides similar observables is the
  • observables and calculated quantities from the AFM measurement (frequency, phase, amplitude, quality factor, etc.) to the surface properties. In contact resonance typically the Kelvin–Voigt model [40] is used, which consists of a linear spring in parallel with a damper (dashpot). It is incorporated into the
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Published 26 Sep 2014

Trade-offs in sensitivity and sampling depth in bimodal atomic force microscopy and comparison to the trimodal case

  • Babak Eslami,
  • Daniel Ebeling and
  • Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1144–1151, doi:10.3762/bjnano.5.125

Graphical Abstract
  • position becomes flatter with respect to the cantilever position above the surface when the first eigenmode amplitude is increased, whereas Figure 5b shows that the phase curve slope behaves similarly for different values of the quality factor (although the cantilever quality factor cannot be arbitrarily
  • changed, the effective quality factor can vary significantly during the measurement due to the dissipative tip–sample interactions, which also cause a decrease in amplitude that leads to additional changes in eigenmode sensitivity [22]). In general, steeper responses of the imaging variables are desired
  • , which is equipped with bimodal imaging modes. We used a Bruker (Santa Barbara, CA, USA) MPP-33120 cantilever with first two resonance frequencies at 45.99 and 284.39 kHz, respectively, fundamental force constant of 7.3 N/m and fundamental quality factor of 236. The amplitude of the first eigenmode was
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Published 24 Jul 2014

Resonance of graphene nanoribbons doped with nitrogen and boron: a molecular dynamics study

  • Ye Wei,
  • Haifei Zhan,
  • Kang Xia,
  • Wendong Zhang,
  • Shengbo Sang and
  • Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 717–725, doi:10.3762/bjnano.5.84

Graphical Abstract
  • discussed. A systematic study of the vibrational properties of graphene doped with nitrogen and boron is performed by means of a molecular dynamics simulation. The influence from different density or species of dopants has been assessed. It is found that the impacts on the quality factor, Q, resulting from
  • the resonance of graphene with different dopants, which may benefit their application as resonators. Keywords: dopant; graphene; molecular dynamics simulation; natural frequency; quality factor; resonance; Introduction Graphene has drawn intensive interest since its discovery in 2005 [1]. It has
  • the resonance properties of graphene, emphasis has been put on the quality factor, Q, and resonance frequency. These values are calculated following the commonly utilized estimation schemes by previous researchers [28][29]. That is, Q is defined as the ratio between the total system energy and the
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Published 27 May 2014

Control theory for scanning probe microscopy revisited

  • Julian Stirling

Beilstein J. Nanotechnol. 2014, 5, 337–345, doi:10.3762/bjnano.5.38

Graphical Abstract
  • poles. Instead the above equations should be used in conjunction with real physical values from a SPM system to understand its stability. As an example we will include a mechanical resonance for the z-piezo relative to its equilibrium position at its input voltage where Q is the quality factor of the
  • excited by high gains. The system can be made stable under higher gains by increasing the eigenfrequency or decreasing the Q of the resonator. For these reasons components with a high quality factor and a low resonant frequency are unsuitable as part of the SPM scanners. In Figure 5a the PI controller
  • output for a range of mechanical eigenfrequencies with a constant quality factor is plotted against time. Arbitrary units are used for both time and the PI output as the evolution under increasing eigenfrequency is valid for any magnitude. The y-axis is labelled PI output, not extension, as these are no
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Published 21 Mar 2014

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

  • Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 298–307, doi:10.3762/bjnano.5.33

Graphical Abstract
  • momentary excitation because the oscillation of the higher eigenmodes begins with the tip–sample impact, governed by the frequency and amplitude of the fundamental eigenmode, and decays in between successive taps of the cantilever. This fast decay occurs because the quality factor of the higher eigenmodes
  • individual eigenmode is strongly dependent on the imaging conditions. This is illustrated in Figure 3 for two cases involving different quality factor and higher mode amplitudes. In general, higher modes are more likely to be perturbed when their free amplitude is small (discussions on this topic can be
  • induced by the tip–sample forces. The situation becomes more favorable as the higher mode quality factor increases such that the phase and amplitude relaxation becomes slower and intermixing of transients from different cycles occurs, similar to what happens in air environments. Specifically, for the i-th
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Published 14 Mar 2014

Frequency, amplitude, and phase measurements in contact resonance atomic force microscopies

  • Gheorghe Stan and
  • Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 278–288, doi:10.3762/bjnano.5.30

Graphical Abstract
  • Lorentzian curve [10][11]. This calculation allows mapping of the resonance frequency and quality factor across the sample, from which viscoelastic properties can also be inferred. In contrast, in the dual-amplitude resonance tracking (DART) method, the frequency response curve is rapidly inferred from the
  • the increase in contact damping. An interesting behaviour is observed also in the maps of quality factor Q (Figure 7d and 7e for the first eigenmode and Figure 8d and 8e for the second eigenmode), calculated as the ratio of the resonance frequency to the width of the resonance peak, ωn/Δω. In general
  • , the quality factor is directly associated with the damping response of the system. However, as it can be seen in Figure 7d and 7h, it depends on both the contact stiffness and contact damping. The Q-factor is almost independent of contact stiffness for the second UAFM and AFAM eigenmodes, in which
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Published 12 Mar 2014

Unlocking higher harmonics in atomic force microscopy with gentle interactions

  • Sergio Santos,
  • Victor Barcons,
  • Josep Font and
  • Albert Verdaguer

Beilstein J. Nanotechnol. 2014, 5, 268–277, doi:10.3762/bjnano.5.29

Graphical Abstract
  • motion of the mth eigenmode where k(m), Q(m), ω(m), and z(m) are the spring constant, quality factor, natural frequency and position of the mth eigenmode. The term FD stands for the external driving force where the subscript without brackets, n, indicates the harmonic number. Note that here ωn = nω
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Published 11 Mar 2014

Exploring the retention properties of CaF2 nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

  • Matthias Wasem,
  • Joachim Köser,
  • Sylvia Hess,
  • Enrico Gnecco and
  • Ernst Meyer

Beilstein J. Nanotechnol. 2014, 5, 36–43, doi:10.3762/bjnano.5.4

Graphical Abstract
  • by tip–sample interactions. If the cantilever has a normal spring constant k and is driven sinusoidally with the amplitude A0 and drive frequency ω0, we can calculate the average power dissipated by tip–sample interactions as where A is the damped amplitude at the given set point, Qcant the quality
  • factor of the cantilever and the phase angle. According to this equation the power lost by tip–sample interaction is proportional to the sine of the phase-lag. It is important to note that Equation 2 allows to calculate the total energy lost by tip–sample interactions but does not reveal how it is lost
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Published 13 Jan 2014

Noise performance of frequency modulation Kelvin force microscopy

  • Heinrich Diesinger,
  • Dominique Deresmes and
  • Thierry Mélin

Beilstein J. Nanotechnol. 2014, 5, 1–18, doi:10.3762/bjnano.5.1

Graphical Abstract
  • the theoretical values derived from both thermal probe excitation and deflection sensor noise. Kobayashi et al. [6] focus on noise propagation in low quality factor (low-Q) environments for the application in liquids. Polesel-Maris et al. [7] studied the noise propagation in both amplitude and phase
  • same closed loop response. Phase detector gain - phase as function of frequency shift We shall study the phase difference between a passive oscillator and a frequency modulated drive signal. If a resonator described by a quality factor Q and a resonance frequency f0 is excited by a frequency modulated
  • of the Lorentzian with its high quality factor, it is sufficient to use one branch of the Lorentzian, and expressed in degrees we obtain: This expression gives the phase noise with the use of a lock-in amplifier. It had been derived in a similar way by Rast et al. [13]. It may not be valid for other
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Published 02 Jan 2014

Peak forces and lateral resolution in amplitude modulation force microscopy in liquid

  • Horacio V. Guzman and
  • Ricardo Garcia

Beilstein J. Nanotechnol. 2013, 4, 852–859, doi:10.3762/bjnano.4.96

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  • of motion for the microcantilever–tip system is approximated by using the point-mass model [25], where m is the effective cantilever mass that includes the added mass of the fluid, and ω0, Q, k and Fts are, respectively, angular resonant frequency, quality factor, spring constant and tip–sample
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Published 06 Dec 2013

Multiple regimes of operation in bimodal AFM: understanding the energy of cantilever eigenmodes

  • Daniel Kiracofe,
  • Arvind Raman and
  • Dalia Yablon

Beilstein J. Nanotechnol. 2013, 4, 385–393, doi:10.3762/bjnano.4.45

Graphical Abstract
  • approximation is made by keeping only the first N eigenmodes. We take N = 4 in this work. This reduces the original equation to a set of four ordinary differential equations: where qi(t), ωi, Qi, and ki, are the tip deflection, natural frequency (rad/s), quality factor, and equivalent stiffness, respectively
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Published 21 Jun 2013

Polynomial force approximations and multifrequency atomic force microscopy

  • Daniel Platz,
  • Daniel Forchheimer,
  • Erik A. Tholén and
  • David B. Haviland

Beilstein J. Nanotechnol. 2013, 4, 352–360, doi:10.3762/bjnano.4.41

Graphical Abstract
  • drive force and a time-dependent tip–surface force where the dot denotes differentiation with respect to time, ω0, Q and kc are the mode’s resonance frequency, quality factor and spring constant respectively, and h is the static equilibrium position of the tip above the surface. One should note that the
  • cantilever (Bruker MPP-11120) was calibrated by a noninvasive thermal method [30] and had a resonance frequency of f0 = 229.802 kHz, a quality factor of Q = 396.9 and a spring constant of kc = 16.0 N m−1. The slow surface approach velocity was 2 nm s−1. PS (Mw = 280 kDa, Sigma-Aldrich) and PMMA (Mw = 120 kDa
  • , Sigma-Aldrich) were spin-cast from toluene solution with a concentration of 0.53 %wt at a ratio of 3:1 (PMMA:PS). The sample was scanned in a Bruker Multimode 2 AFM system with a cantilever BS 300Al-G (Budget Sensors) having a resonance frequency f0 = 343.379 kHz, quality factor Q = 556.9 and spring
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Published 10 Jun 2013

High-resolution nanomechanical analysis of suspended electrospun silk fibers with the torsional harmonic atomic force microscope

  • Mark Cronin-Golomb and
  • Ozgur Sahin

Beilstein J. Nanotechnol. 2013, 4, 243–248, doi:10.3762/bjnano.4.25

Graphical Abstract
  • measuring its resonance frequency and quality factor (either by frequency sweeps or from the thermal peak in the noise spectrum). The gain of the torsional mode, defined as the photodetector signal corresponding to a unit amount of a quasi-static force acting on the tip, is determined by independently
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Published 05 Apr 2013
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