Characterization of the mechanical properties of qPlus sensors

• Jan Berger,
• Martin Švec,
• Martin Müller,
• Martin Ledinský,
• Antonín Fejfar,
• Pavel Jelínek and
• Zsolt Majzik

Beilstein J. Nanotechnol. 2013, 4, 1–9, doi:10.3762/bjnano.4.1

• thermal noise spectrum. We show that all three methods give very similar results. Surprisingly, neither the gold wire nor the gluing give rise to significant changes of the stiffness in the case of our home-built sensors. Furthermore we describe a fast and cost-effective way to perform Cleveland’s method

• . Keywords: AFM; Cleveland’s method; cross talk; force; qPlus; stiffness; STM; thermal noise; tuning fork; Introduction The invention of scanning tunneling microscopy [1] and atomic force microscopy (AFM) [2] opened new horizons in characterization and modification of surfaces and nanostructures. STM is

• determined by using the same PLL as for the ambient measurement. A high-quality PC sound card ASUS Xonar Essence ST in combination with a free FFT software Spectrum Lab (Audio Signal Analyser) was used to record thermal-noise density spectra. Results and Discussion We carried out a series of measurements of

Spring constant of a tuning-fork sensor for dynamic force microscopy

• Dennis van Vörden,
• Manfred Lange,
• Merlin Schmuck,
• Nico Schmidt and
• Rolf Möller

Beilstein J. Nanotechnol. 2012, 3, 809–816, doi:10.3762/bjnano.3.90

• resonance frequency [12][13][14]. By measuring the amplitude of the thermal noise, k can be evaluated in situ, e.g., in a vacuum system prior to the measurement, without any modification of the experimental arrangement [15][16][17][18][19][20]. However, this requires a good signal-to-noise ratio for the

• we compare the results for the determination of the spring constant of tuning fork sensors in the qPlus configuration [1][2] based on the following methods: a simple calculation for a cantilever beam; the measured deflection as a function of the applied force; the thermal noise; and a numerical

Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM

• Cagri Üzüm,
• Johannes Hellwig,
• Narayanan Madaboosi,
• Dmitry Volodkin and
• Regine von Klitzing

Beilstein J. Nanotechnol. 2012, 3, 778–788, doi:10.3762/bjnano.3.87

• measurements. Although the spring constant kc was given by the manufacturer as 0.05 N/m (unless stated otherwise), its exact value was determined before each measurement by the thermal noise method, which is a built-in procedure in the MFP-3D instrument (Asylum Research, CA, USA). Thickness measurements Two

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

Mapping mechanical properties of organic thin films by force-modulation microscopy in aqueous media

• Jianming Zhang,
• Zehra Parlak,
• Carleen M. Bowers,
• Terrence Oas and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 464–474, doi:10.3762/bjnano.3.53

• curve taken before an FMM experiment. The spring constant of each cantilever was calculated from the power spectral density of the thermal noise fluctuations. Since FMM is a modified contact mode AFM method, frictional forces may affect the measurements. Friction leads to lateral twisting of the

Wavelet cross-correlation and phase analysis of a free cantilever subjected to band excitation

• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2012, 3, 294–300, doi:10.3762/bjnano.3.33

• ], impulsive cantilever excitation [5] or thermal-noise excitation [6][7][8][9]. Thermal noise analysis has been performed, with the aid of wavelet transforms, to characterize the time–frequency response of a thermally excited cantilever in dynamic force spectroscopy [10][11][12]. In these previous works, the

• traditional Fourier spectra. Regarding environmental noise, it has been demonstrated that by using only thermal excitation it is possible to retrieve useful information from force spectroscopy [11] with a single approach curve under standard operating conditions. Regarding the thermal noise, the excitation

• signals must have amplitudes exceeding that of the thermal noise, because averaging is limited or absent. In this case, the choice of the excitation amplitude depends on the type of cantilever, on its quality factor and on the parameters to be measured. We anticipated that only extremely low amplitude

Pulse-response measurement of frequency-resolved water dynamics on a hydrophilic surface using a Q-damped atomic force microscopy cantilever

• Masami Kageshima

Beilstein J. Nanotechnol. 2012, 3, 260–266, doi:10.3762/bjnano.3.29

• , resonance-free cantilever with the input waveform [25]. The Q-control gain was fixed to this value throughout the measurement. Figure 4 shows a comparison of the power spectrum density (PSD) of thermal noise in the cantilever-deflection signal before and after Q-control gain optimization. The peaks in the

• , thick solid, and fine solid lines indicate the input-voltage signal, current in the electromagnet, and cantilever deflection, respectively. The cantilever swing amplitude corresponds to about 4 nm. Comparison of the power spectrum density (PSD) of thermal noise in the cantilever-deflection signal before

qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution

• Maximilian Schneiderbauer,
• Daniel Wastl and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2012, 3, 174–178, doi:10.3762/bjnano.3.18

• determine the sensitivity of the experimental setup, and thus the minimum detectable averaged force gradient , one has to calculate the frequency noise of the setup δ(Δf). In FM-AFM setups δ(Δf) is a sum of three uncorrelated noise sources [13][14]: Thermal noise deflection-detector noise and oscillator

Charge transport in a zinc–porphyrin single-molecule junction

• Mickael L. Perrin,
• Christian A. Martin,
• Ferry Prins,
• Ahson J. Shaikh,
• Rienk Eelkema,
• Jan H. van Esch,
• Jan M. van Ruitenbeek,
• Herre S. J. van der Zant and
• Diana Dulić

Beilstein J. Nanotechnol. 2011, 2, 714–719, doi:10.3762/bjnano.2.77

• stability increases, and both the thermal noise and thermal broadening decrease. We therefore cooled down the junctions to cryogenic temperature (6 K) while keeping the zero-bias conductance at a fixed value (around 1∙10−4 G0) with a feedback loop. In Figure 3a and Figure 3b, we present low-temperature I(V

Tip-sample interactions on graphite studied using the wavelet transform

• Giovanna Malegori and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2010, 1, 172–181, doi:10.3762/bjnano.1.21

• k = 0.13 N/m [20]. For each cantilever the elastic constant is evaluated both by the Sader method [20] and the thermal noise method applied to the first flexural mode [21][22]. Both methods agree within 5%. The piezoscanning system is based on a single scanner tube with a maximum vertical extension

• of 2 μm. The experiments consisted in acquiring the temporal evolution of the thermal noise as a function of the tip-sample distance. The thermal noise signal measured by the beam deflection system is sampled with the digitizing oscilloscope while the tip moves toward the surface. The piezoscanner is

Sensing surface PEGylation with microcantilevers

• Natalija Backmann,
• Natascha Kappeler,
• Thomas Braun,
• François Huber,
• Hans-Peter Lang,
• Christoph Gerber and
• Roderick Y. H. Lim

Beilstein J. Nanotechnol. 2010, 1, 3–13, doi:10.3762/bjnano.1.2

• ± 0.1 nm for L and s, respectively. The data collected beyond a certain D is scattered being less than the minimum detectable force, which is given by the thermal noise of the AFM-cantilever: Fmin = (kBT × kAFM)1/2 ≈ 5 pN. The weak repulsion at ~5 nm in the lower curve indicates that the PEG chains are