scholarly journals Current measurements in the intermittent-contact mode of atomic force microscopy using the Fourier method: a feasibility analysis

2020 ◽  
Vol 11 ◽  
pp. 453-465 ◽  
Author(s):  
Berkin Uluutku ◽  
Santiago D Solares

Atomic force microscopy (AFM) is an important tool for measuring a variety of nanoscale surface properties, such as topography, viscoelasticity, electrical potential and conductivity. Some of these properties are measured using contact methods (static contact or intermittent contact), while others are measured using noncontact methods. Some properties can be measured using different approaches. Conductivity, in particular, is mapped using the contact-mode method. However, this modality can be destructive to delicate samples, since it involves continuously dragging the cantilever tip on the surface during the raster scan, while a constant tip–sample force is applied. In this paper we discuss a possible approach to develop an intermittent-contact conductive AFM mode based on Fourier analysis, whereby the measured current response consists of higher harmonics of the cantilever oscillation frequency. Such an approach may enable the characterization of soft samples with less damage than contact-mode imaging. To explore its feasibility, we derive the analytical form of the tip–sample current that would be obtained for attractive (noncontact) and repulsive (intermittent-contact) dynamic AFM characterization, and compare it with results obtained from numerical simulations. Although significant instrumentation challenges are anticipated, the modelling results are promising and suggest that Fourier-based higher-harmonics current measurement may enable the development of a reliable intermittent-contact conductive AFM method.

2016 ◽  
Vol 108 (24) ◽  
pp. 243101 ◽  
Author(s):  
Aymeric Vecchiola ◽  
Pascal Chrétien ◽  
Sophie Delprat ◽  
Karim Bouzehouane ◽  
Olivier Schneegans ◽  
...  

2003 ◽  
Vol 11 (2) ◽  
pp. 42-43
Author(s):  
John T. Woodward

What is the best cantilever for intermittent contact mode (often called Tapping Mode™) atomic force microscope (AFM) imaging under water? This is a question I hear often and one that recently generated some interesting discussion on an AFM newsgroup (more on the newsgroup below). The ability of the AFM to image samples En physiologically relevant environments has made it a popular technique in the biological sciences. However, because scanning the AFM tip in contact mode easily perturbs many biological samples, it was the advent of intermittent contact modes that lead to AFM's widespread use in biology.


2007 ◽  
Vol 06 (05) ◽  
pp. 345-348
Author(s):  
E. TRANVOUEZ ◽  
A. DESCAMPS ◽  
G. BREMOND ◽  
A. TURALA ◽  
P. REGRENY ◽  
...  

In order to create suitable nanoholes for quantum dot (QD) localization on InP and GaAs surfaces, we used atomic force microscopy in an intermittent contact mode coupled with a modulated voltage to realized local anodization at a nanometer scale. This method leads, after a few tens of milliseconds of oxidation, to an oxide height saturation and a low lateral growth rate for both surfaces. These specific results were used to control separately both the depth and the diameter of holes and to obtain compatible pattern for QD growth. We also demonstrated the thermal stability of these patterns at compatible temperatures with the InAs QD growth. First, results of QD growth on these patterns are presented.


2011 ◽  
Vol 17 (4) ◽  
pp. 587-597 ◽  
Author(s):  
Sergei Magonov ◽  
John Alexander

AbstractWe demonstrate that single-pass Kelvin force microscopy (KFM) and dC/dz measurements in different environments expand the compositional imaging with atomic force microscopy. The KFM and dC/dz studies were performed in the intermittent contact mode with force gradient detection of tip-sample electrostatic interactions. Both factors contribute to sensitive measurements of the surface potential and capacitance gradient with nanometer-scale spatial resolution as it was verified on a broad range of materials: metal alloys, polymers, organic layers, and liquid-like objects. For many samples the surface potential and dC/dz variations complement each other in identification of individual components of heterogeneous materials. In situ imaging in different humidity or vapors of various organic solvents further facilitate recognition of the constituents of multicomponent polymer samples due to selective swelling of components.


Small ◽  
2012 ◽  
Vol 8 (8) ◽  
pp. 1264-1269 ◽  
Author(s):  
Senli Guo ◽  
Santiago D. Solares ◽  
Vadym Mochalin ◽  
Ioannis Neitzel ◽  
Yury Gogotsi ◽  
...  

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