High-sensitivity quantitative Kelvin probe microscopy by noncontact ultra-high-vacuum atomic force microscopy

Sommerhalter, Ch.; Matthes, Th.W.; Glatzel, Thilo; Jäger-Waldau, Arnulf; Lux‐Steiner, Martha Ch.

doi:10.1063/1.124357

Cited by 251 publications

(158 citation statements)

References 21 publications

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“…Since then, Kelvin probe force microscopy (KPFM) has undergone significant advances in both sensitivity [4][5][6][7] and resolution [8][9][10], with a broad spectrum of configurations now available. KPFM has been applied to study a variety of materials, including organic, biological, and energy conversion and storage-related materials.…”

Section: Introductionmentioning

confidence: 99%

Open loop Kelvin probe force microscopy with single and multi-frequency excitation

et al. 2013

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Abstract. Conventional Kelvin probe force microscopy (KPFM) relies on closed loop (CL) bias feedback for the determination of surface potential (SP). However, SP measured by CL-KPFM has been shown to be strongly influenced by the choice of measurement parameters due to non-electrostatic contributions to the input signal of the bias feedback loop. This often leads to systematic errors of several hundred mV and can also result in topographical crosstalk. Here, open loop (OL)-KPFM modes are investigated as a means of obtaining a quantitative, crosstalk free measurement of the SP of graphene grown on Cu foil, and are directly contrasted with CL-KPFM. OL-KPFM operation is demonstrated in both single and multi-frequency excitation regimes, yielding quantitative SP measurements. The SP difference between single and multilayer graphene structures using OL-KPFM was found to be 63 ± 11 mV, consistent with values previously reported by CL-KPFM. Furthermore, the same relative potential difference between Al 2 O 3 -coated graphene and Al 2 O 3 -coated Cu was observed using both CL and OL techniques. We observe an offset of 55 mV between absolute SP values obtained by OL and CL techniques, which is attributed to the influence of non-electrostatic contributions to the input of the bias feedback used in CL-KPFM.

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Section: Introductionmentioning

confidence: 99%

Open loop Kelvin probe force microscopy with single and multi-frequency excitation

et al. 2013

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“…Because the scope of this article is primarily theoretical, we don't further consider such experimental difficulties, but focus our attention on still controversial atomic-scale variations of the so-called local CPD or V LCP D on large defect-free surface areas. Thus we deliberately leave out local changes due to charged surface defects 4, 17,20 or adsorbates 18,21 which have recently attracted considerable attention, also in theory.…”

Section: -18mentioning

confidence: 99%

Multiscale approach for simulations of Kelvin probe force microscopy with atomic resolution

et al. 2012

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The distance dependence and atomic-scale contrast recently observed in nominal contact potential difference (CPD) signals simultaneously recorded by KPFM using non-contact atomic force microscopy (NCAFM) on defect-free surfaces of insulating, as well as semiconducting samples, have stimulated theoretical attempts to explain such effects. Especially in the case of insulators, it is not quite clear how the applied bias voltage affects electrostatic forces acting on the atomic scale. We attack this problem in two steps. First, the electrostatics of the macroscopic tip-cantilever-sample system is treated by a finite-difference method on an adjustable nonuniform mesh. Then the resulting electric field under the tip apex is inserted into a series of atomistic wavelet-based density functional theory (DFT) calculations. Results are shown for a realistic neutral but reactive silicon nano-scale tip interacting with a NaCl(001) sample. Bias-dependent forces and resulting atomic displacements are computed to within an unprecedented accuracy.Theoretical expressions for amplitude modulation (AM) and frequency modulation (FM) KPFM signals and for the corresponding local contact potential differences (LCPD) are obtained by combining the macroscopic and atomistic contributions to the electrostatic force component generated at the voltage modulation frequency, and evaluated for several tip oscillation amplitudes A up to 10 nm. For A = 0.1Å, the computed LCPD contrast is proportional to the slope of the atomistic force versus bias in the AM mode and to its derivative with respect to the tip-sample separation in the FM mode. Being essentially constant over a few Volts, this slope is the basic quantity which determines variations of the atomic-scale LCPD contrast. Already above A = 1Å, the LCPD contrasts in both modes exhibit almost the same spatial dependence as the slope. In the AM mode, this contrast is approximately proportional to A −1/2 , but remains much weaker than the contrast in the FM mode, which drops somewhat faster as A is increased. These trends are a consequence of the macroscopic contributions to the KPFM signal, which are stronger in the AM-mode and especially important if the sample is an insulator even at sub-nanometer separations where atomic-scale contrast appears.

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“…These electrons form ideal Fermi gas with the temperature that is below the Fermi temperature. Because of the degeneracy of the gas, we cannot register edge or defect states in the valence band of our sample similarly to [22,23] results. If the localized surface states are registered either by spreading resistance atomic force microscopy or by Kelvin probe force microscopy, the results have to be invariant to the both scan velocity and direction.…”

Section: Discussionmentioning

confidence: 99%

Semiconductor Physics, Quantum Electronics & Optoelectronics. 2017. V. 20, N 2. P. 185-190. DOI: https://doi.org/10.15407/spqeo20.02.185 London forces in highly oriented pyrolytic graphite

Poperenko¹

2017

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. Surface of highly oriented pyrolytic graphite with terrace steps was studied using scanning tunneling microscopy with high spatial resolution. Spots with positive and negative charges were found in the vicinity of the steps. Values of the charges depended both on the microscope needle scan velocity and on its motion direction. The observed effect was theoretically explained with account of London forces that arise between the needle tip and the graphite surface. In this scheme, a terrace step works as a nanoscale diode for surface electric currents.

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High-sensitivity quantitative Kelvin probe microscopy by noncontact ultra-high-vacuum atomic force microscopy

Cited by 251 publications

References 21 publications

Open loop Kelvin probe force microscopy with single and multi-frequency excitation

Open loop Kelvin probe force microscopy with single and multi-frequency excitation

Multiscale approach for simulations of Kelvin probe force microscopy with atomic resolution

Semiconductor Physics, Quantum Electronics & Optoelectronics. 2017. V. 20, N 2. P. 185-190. DOI: https://doi.org/10.15407/spqeo20.02.185 London forces in highly oriented pyrolytic graphite

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