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

1999 ◽  
Vol 75 (2) ◽  
pp. 286-288 ◽  
Author(s):  
Ch. Sommerhalter ◽  
Th. W. Matthes ◽  
Th. Glatzel ◽  
A. Jäger-Waldau ◽  
M. Ch. Lux-Steiner
Keyword(s):  
Atomic Force Microscopy ◽  
High Vacuum ◽  
High Sensitivity ◽  
Ultra High Vacuum ◽  
Kelvin Probe ◽  
Probe Microscopy ◽  
Kelvin Probe Microscopy ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Elucidating the charge state of an Au nanocluster on the oxidized/reduced rutile TiO2 (110) surface using non-contact atomic force microscopy and Kelvin probe force microscopy

2020 ◽  
Vol 2 (6) ◽  
pp. 2371-2375 ◽  
Author(s):  
Yuuki Adachi ◽  
Huan Fei Wen ◽  
Quanzhen Zhang ◽  
Masato Miyazaki ◽  
Yasuhiro Sugawara ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Charge State ◽  
High Vacuum ◽  
Kelvin Probe Force Microscopy ◽  
Ultra High Vacuum ◽  
Kelvin Probe ◽  
Au Nanoclusters ◽  
Rutile Tio2 ◽  
Force Microscopy ◽  
Atomic Force

The charge state of Au nanoclusters on oxidized/reduced rutile TiO2 (110) surfaces were investigated by a combination of non-contact atomic force microscopy and Kelvin probe force microscopy at 78 K under ultra-high vacuum.

Determination of the Physical Properties of Oil Sands Components using Scanning Probe Microscopy

2015 ◽  
Vol 1754 ◽  
pp. 69-74
Author(s):  
Ravi Gaikwad ◽  
Tinu Abraham ◽  
Aharnish Hande ◽  
Fatemeh Bakhtiari ◽  
Siddhartha Das ◽  
...  
Keyword(s):  
Oil Sands ◽  
Structural Changes ◽  
Rational Approach ◽  
Kelvin Probe ◽  
Scanning Calorimetry ◽  
Probe Microscopy ◽  
Kelvin Probe Microscopy ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTAtomic force microscopy is employed to study the structural changes in the morphology and physical characteristics of asphaltene aggregates as a function of temperature. The exotic fractal structure obtained by evaporation-driven asphaltene aggregates shows an interesting dynamics for a large range of temperatures from 25°C to 80°C. The changes in the topography, surface potential and adhesion are unnoticeable until 70°C. However, a significant change in the dynamics and material properties is displayed in the range of 70°C - 80°C, during which the aspahltene aggregates acquire ‘liquid-like’ mobility and fuse together. This behaviour is attributed to the transition from the pure amorphous phase to a crystalline liquid phase which occurs at approximately 70°C as shown by using Differential Scanning Calorimetry (DSC). Additionally, the charged nature of asphaltenes and bitumen is also explored using kelvin probe microscopy. Such observations can lead to the development of a rational approach to the fundamental understanding of asphaltene aggregation dynamics and may help in devising novel techniques for the handling and separation of asphaltene aggregates using dielectrophoretic methods.

Laser cleaning of exfoliated graphene

2012 ◽  
Vol 1455 ◽  
Author(s):  
Oliver Ochedowski ◽  
Benedict Kleine Bußmann ◽  
Marika Schleberger
Keyword(s):  
Local Heating ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ambient Conditions ◽  
Kelvin Probe ◽  
Structural Modifications ◽  
Force Microscopy ◽  
Exfoliated Graphene ◽  
Atomic Force ◽  
P Type

ABSTRACTWe have employed atomic force and Kelvin-Probe force microscopy to study graphene sheets exfoliated on TiO2 under the influence of local heating achieved by laser irradiation. Exfoliation and irradiation took place under ambient conditions, the measurements were performed in ultra high vacuum. We show that after irradiation times of 6 min, an increase of the surface potential is observed which indicates a decrease of p-type carrier concentration. We attribute this effect to the removal of adsorbates like water and oxygen. After irradiation times of 12 min our topography images reveal severe structural modifications of graphene. These resemble the nanocrystallite network which form on graphene/SiO2 but after much longer irradiation times. From our results we propose that short laser heating at moderate powers might offer a way to clean graphene without inducing unwanted structural modifications.

Development of a Self-Excited Oscillator for SI-Traceable Measurements in Atomic Force Microscopy

2008 ◽  
Author(s):  
Gregory W. Vogl ◽  
Jon R. Pratt
Keyword(s):  
Atomic Force Microscopy ◽  
International System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Force Microscopy ◽  
Atomic Force ◽  
Force Transducers ◽  
Analog Control ◽  
System Of Units ◽  
Excited Oscillator

A new self-excited micro-oscillator is proposed as a velocity reference that could aid the dissemination of nanonewton-level forces that are traceable to the International System of Units (SI). An analog control system is developed to keep the actuation side of the device oscillating sinusoidally with an amplitude that is fairly insensitive to the quality factor. Consequently, the device can be calibrated as a velocity reference in air and used in ultra-high vacuum with a velocity shift of less than one percent. Hence, the calibrated micro-oscillator could be used with electrostatic forces to calibrate cantilevers used for atomic force microscopy (AFM) as SI-traceable force transducers. Furthermore, the calibrated micro-oscillator could potentially be used as an AFM sensor to achieve atomic resolutions on par with those realized in frequency-modulation AFM (FM-AFM) with quartz tuning forks.

Atomic-Force Microscopy with piezoresistive cantilevers

1994 ◽  
Vol 52 ◽  
pp. 1064-1065
Author(s):  
M. Tortonese ◽  
F. J. Giessibl
Keyword(s):  
Atomic Force Microscopy ◽  
Electron Tunneling ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Cantilever Deflection ◽  
Force Microscopy ◽  
Large Samples ◽  
Atomic Force ◽  
High Lateral Resolution ◽  
Piezoresistive Cantilevers

The atomic force microscope (AFM) works by measuring the deflection of a cantilever as it is scanned over a sample. A sharp tip at the end of the cantilever is responsible for the high lateral resolution achieved with the AFM. There are several ways to measure the deflection of the cantilever. The technique used to measure the deflection of the cantilever most often dictates the mechanical complexity and stability of the instrument. Electron tunneling, interferometry and capacitive sensors have been used successfully. The most common way to measure the cantilever deflection is by means of an optical deflection detector.The piezoresistivc cantilever offers a new way to measure the deflection of the cantilever, with performances comparable to the performances of other deflection detectors, and with the advantage that the sensor is incorporated in the cantilever. This simplifies the design and operation of the microscope In particular, the piezoresistive cantilever facilitates the use and often improves the performances of an AFM when operated in ultra high vacuum (UHV), at low temperature, or when used to image large samples.

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

2012 ◽  
Vol 3 ◽  
pp. 25-32 ◽  
Author(s):  
Adam Sweetman ◽  
Sam Jarvis ◽  
Rosanna Danza ◽  
Philip Moriarty
Keyword(s):  
Atomic Force Microscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Dissipated Energy ◽  
Tunnel Current ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Characteristic Imaging

Background: Noncontact atomic force microscopy (NC-AFM) now regularly produces atomic-resolution images on a wide range of surfaces, and has demonstrated the capability for atomic manipulation solely using chemical forces. Nonetheless, the role of the tip apex in both imaging and manipulation remains poorly understood and is an active area of research both experimentally and theoretically. Recent work employing specially functionalised tips has provided additional impetus to elucidating the role of the tip apex in the observed contrast. Results: We present an analysis of the influence of the tip apex during imaging of the Si(100) substrate in ultra-high vacuum (UHV) at 5 K using a qPlus sensor for noncontact atomic force microscopy (NC-AFM). Data demonstrating stable imaging with a range of tip apexes, each with a characteristic imaging signature, have been acquired. By imaging at close to zero applied bias we eliminate the influence of tunnel current on the force between tip and surface, and also the tunnel-current-induced excitation of silicon dimers, which is a key issue in scanning probe studies of Si(100). Conclusion: A wide range of novel imaging mechanisms are demonstrated on the Si(100) surface, which can only be explained by variations in the precise structural configuration at the apex of the tip. Such images provide 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.

Distinguishing negatively-charged and highly conductive dislocations in gallium nitride using scanning Kelvin probe and conductive atomic force microscopy

2002 ◽  
Vol 743 ◽  
Author(s):  
Blake S. Simpkins ◽  
Edward T. Yu ◽  
Patrick Waltereit ◽  
James S. Speck
Keyword(s):  
Atomic Force Microscopy ◽  
Kelvin Probe ◽  
Conductive Atomic Force Microscopy ◽  
Kelvin Probe Microscopy ◽  
Force Microscopy ◽  
Spatially Correlated ◽  
Atomic Force ◽  
Scanning Kelvin Probe ◽  
Dislocation Type ◽  
Distinct Features

ABSTRACTScanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C-AFM) are used to image surfaces of GaN grown by molecular beam epitaxy (MBE). Numerical simulations are used to assist in the interpretation of SKPM images. Detailed analysis of the same area using both techniques allows imaging of surface potential variations arising from the presence of negatively charged dislocations and dislocation-related current leakage paths. Correlations between the charge state of dislocations, conductivity of leakage current paths, and possibly dislocation type can thereby be established. Approximately 25% of the leakage paths appear to be spatially correlated with negatively charged dislocation features. This is approximately the level of correlation expected due to spatial overlap of randomly distributed, distinct features of the size observed, suggesting that the negatively charged dislocations are distinct from those responsible for localized leakage paths found in GaN. The effects of charged dislocation networks on the local potential profile is modeled and discussed.

Nonlinear Multi-Mode Dynamics of a Microbeam for Noncontact Atomic Force Microscopy in Ultra-High Vacuum

2005 ◽  
Author(s):  
W. Wu ◽  
S. Pragai ◽  
O. Gottlieb
Keyword(s):  
Atomic Force Microscopy ◽  
High Vacuum ◽  
Closed Form Solution ◽  
Form Solution ◽  
Ultra High Vacuum ◽  
Atomic Interaction ◽  
Internal Resonances ◽  
Force Microscopy ◽  
Atomic Force ◽  
Multi Mode

We study the nonlinear multi-mode dynamics of a microbeam for noncontact atomic force microscopy in ultra-high vacuum. A boundary-value problem that includes a coupled linear thermo- and viscoelastic field with a localized nonlinear atomic interaction force, augmented by the linearized heat equation, is reduced to a modal dynamical system via Galerkin’s method. An equivalent linear thermoelastic quality factor is obtained and compared with a closed form solution. A numerically obtained escape curve defines valid operating parameters for low damping conditions. Primary, secondary and coupled internal resonances of a three-mode system are examined to reveal a rich bifurcation structure.

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