Influence of the adsorption geometry of PTCDA on Ag(111) on the tip–molecule forces in non-contact atomic force microscopy

• Gernot Langewisch,
• Jens Falter,
• André Schirmeisen and
• Harald Fuchs

Beilstein J. Nanotechnol. 2014, 5, 98–104, doi:10.3762/bjnano.5.9

• tunneling microscopy and scanning tunneling spectroscopy studies of PTCDA adsorbed on Ag(111) have revealed differences in the electronic structure of the molecules depending on their adsorption geometry. In the work presented here, high-resolution 3D force spectroscopy measurements at cryogenic

• both cases. This result demonstrates the capability of 3D force spectroscopy to detect even small effects in the electronic properties of organic adsorbates. Keywords: atomic force microscopy; organic molecules; three-dimensional (3D) force spectroscopy; Introduction Perylene-3,4,9,10-tetracarboxylic

• -resolution three-dimensional (3D) force spectroscopy [10] to investigate the complete force field quantitatively, while starting at large tip–sample distances with no force interactions down to the regime of repulsive forces. Experimental The experiments have been performed with a commercial low-temperature

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

• polynomial force reconstruction from experimental intermodulation atomic force microscopy (ImAFM) data. We study the tip–surface force during a slow surface approach and compare the results with amplitude-dependence force spectroscopy (ADFS). Based on polynomial force reconstruction we generate high

• to spectral data, and we demonstrate how it can be adapted to a force quadrature picture. Keywords: AFM; atomic force microscopy; force spectroscopy; multifrequency; intermodulation; polynomial; Introduction The combination of high-resolution imaging [1][2][3][4] and high-accuracy force

• data for intermodulation AFM (ImAFM) [17][19]. Here, we demonstrate, for the first time, polynomial force reconstruction on experimental ImAFM data and compare it with reconstruction based on amplitude-dependence force spectroscopy (ADFS) [20]. Moreover, fitting a force model to the polynomial

Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case

• Daniel Ebeling and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 198–207, doi:10.3762/bjnano.4.20

• . Finally, FM-AFM also has the potential advantage to enable real-time 3D force spectroscopy in multifrequency operation, in the limit of small response time. As previously simulated [31][32], if a sufficiently high eigenmode were self-excited while performing intermittent contact imaging with the

Towards 4-dimensional atomic force spectroscopy using the spectral inversion method

• Jeffrey C. Williams and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 87–93, doi:10.3762/bjnano.4.10

• possibility of carrying out 4-dimensional (4D) atomic force spectroscopy. With the extended spectral inversion method it is theoretically possible to measure the tip–sample forces as a function of the three Cartesian coordinates in the scanning volume (x, y and z) and the vertical velocity of the tip, through

• force microscopy (AFM) is the measurement of probe–sample interaction force curves (force spectroscopy), generally based on contact and frequency-modulation methods [1][2][3][4][5][6]. The procedure is generally time-consuming because the acquisition of the force curve for each (x,y) location on the

• depicting the force as a function of the tip–surface separation, as is customary in atomic force spectroscopy (see Figure 1, traditional representation). The purpose of this paper is to introduce an extension of the method, such that the forces can be acquired in 4 dimensions (4D), as a function of the

Interpreting motion and force for narrow-band intermodulation atomic force microscopy

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

Beilstein J. Nanotechnol. 2013, 4, 45–56, doi:10.3762/bjnano.4.5

• , providing deeper insight into the tip–surface interaction. We demonstrate the capabilities of ImAFM approach measurements on a polystyrene polymer surface. Keywords: atomic force microscopy; AFM; frequency combs; force spectroscopy; high-quality-factor resonators; intermodulation; multifrequency

• quadratures FI and FQ, which are independent of details of the tip motion on the slow time scale. Due to this independence, FI and FQ are the input quantities for nearly all force spectroscopy methods in dynamic AFM and thereby they form the basis of quantitative dynamic AFM. Force quadrature reconstruction

• full h–A plane, providing detailed insight into the interaction between tip and surface. We demonstrated the reconstruction of FI and FQ maps experimentally on a PS polymer surface. We hope that the physical interpretation of narrow-band dynamic AFM presented here, will inspire new force-spectroscopy

Calculation of the effect of tip geometry on noncontact atomic force microscopy using a qPlus sensor

• Julian Stirling and
• Gordon A. Shaw

Beilstein J. Nanotechnol. 2013, 4, 10–19, doi:10.3762/bjnano.4.2

• lateral component, raising interesting questions for both calibration and force-spectroscopy measurements. Keywords: atomic force microscopy; force spectroscopy; lateral forces; mechanical vibrations; qPlus; Introduction From imaging of individual chemical bonds [1] to subatomic resolution of the

Probing three-dimensional surface force fields with atomic resolution: Measurement strategies, limitations, and artifact reduction

• Mehmet Z. Baykara,
• Omur E. Dagdeviren,
• Todd C. Schwendemann,
• Harry Mönig,
• Eric I. Altman and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2012, 3, 637–650, doi:10.3762/bjnano.3.73

• fields, including catalysis, thin-film growth, nanoscale device fabrication, and tribology, among others [1]. Shortly after the first atomic-resolution images of surfaces were obtained by noncontact atomic force microscopy (NC-AFM) [2][3], the method of dynamic force spectroscopy (DFS) was introduced

• atoms and molecules laterally on sample surfaces were quantified [34] and the lateral force field on graphite could be studied in detail [20]. Finally, three-dimensional force spectroscopy experiments performed in a liquid environment have revealed the spatial distribution of water molecules at a water

• the influence of the surface force field. The intent of this paper is to provide a comprehensive discussion of all the major limitations intrinsic to three-dimensional force spectroscopy by scanned probes that have to be considered during data interpretation. To that end, the effect that each 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

Modeling noncontact atomic force microscopy resolution on corrugated surfaces

• Kristen M. Burson,
• Mahito Yamamoto and
• William G. Cullen

Beilstein J. Nanotechnol. 2012, 3, 230–237, doi:10.3762/bjnano.3.26

• -AFM) has brought considerable advancement to the atomic-scale study of surfaces, by allowing both atomic-resolution imaging and atomically resolved force spectroscopy. Generally, these advancements have been made on atomically flat crystalline surfaces. Yet, many surfaces of technological interest are

A measurement of the hysteresis loop in force-spectroscopy curves using a tuning-fork atomic force microscope

• Manfred Lange,
• Dennis van Vörden and
• Rolf Möller

Beilstein J. Nanotechnol. 2012, 3, 207–212, doi:10.3762/bjnano.3.23

• gradient between the oscillating tip and a surface (force-spectroscopy measurements). When nonconservative forces act between the tip apex and the surface the oscillation amplitude is damped. The dissipation is caused by bistabilities in the potential energy surface of the tip–sample system, and the

• process can be understood as a hysteresis of forces between approach and retraction of the tip. In this paper, we present the direct measurement of the whole hysteresis loop in force-spectroscopy curves at 77 K on the PTCDA/Ag/Si(111) √3 × √3 surface by means of a tuning-fork-based NC-AFM with an

• about 0.22 eV/cycle. Keywords: atomic force microscopy; energy dissipation; force spectroscopy; hysteresis loop; PTCDA/Ag/Si(111) √3 × √3; Introduction Noncontact atomic force microscopy (NC-AFM) is a powerful tool for the study of surface properties. The invention of the frequency-modulation mode (FM

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

• Adam Sweetman,
• Sam Jarvis,
• Rosanna Danza and
• Philip Moriarty

Beilstein J. Nanotechnol. 2012, 3, 25–32, doi:10.3762/bjnano.3.3

• a valuable resource for theoreticians working on the development of realistic tip structures for NC-AFM simulations. Force spectroscopy measurements show that the tip termination critically affects both the short-range force and dissipated energy. Keywords: force spectroscopy; image contrast

• imaging and force spectroscopy of the Si(100) surface at 5 K by qPlus [21] NC-AFM at zero applied bias, and investigate the influence of different apex types on the qualitative image appearance, and quantitative short-range tip–sample force and dissipation. Experimental details We used a commercial low

• confirmed by force spectroscopy experiments (see discussion below). It is instructive to note that direct comparison of the frequency shift setpoints for each image is not a good measure of the site specific (short-range) tip–sample interaction, as the magnitude of Δf is highly dependent on the macroscopic

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

• information is no more correlated with a single state of the system. There exists a powerful and well developed mathematical tool overcoming these limitations, not yet applied to analyze the dynamic force spectroscopy (DFS) data, the wavelet analysis [10][11]. In this work, we present wavelet theory as an

• has been used in atomic force spectroscopy mainly to denoise or extract data from images [12][13], which is by far the most important application of the wavelet transform. In the following, first we briefly illustrate the Fourier approach to analyze the time traces of the cantilever thermal

• ) surface. All the experiments have been conducted in air, with a relative humidity of less than 50%. Figure 1 schematically shows the experimental apparatus: the electronic noise level is small enought to detect up to five flexural eigenmodes. The optical lever sensitivity is calibrated by taking the force