Modeling the Thermomechanical Interaction Between an Atomic Force Microscope Cantilever and Laser Light

2012 ◽  
Author(s):  
Aarti Chigullapalli ◽  
Jason V. Clark
Keyword(s):  
Laser Beam ◽  
Resonance Frequency ◽  
Atomic Force Microscope ◽  
Laser Power ◽  
Laser Light ◽  
Laser Spot ◽  
Design Parameters ◽  
Atomic Force ◽  
Voltage Signal ◽  
Afm Cantilever

In this paper, we present the first computational model of the thermomechanical interaction between an atomic force microscope (AFM) cantilever and laser light. We validate simulation with experiment. Design parameters of our model include AFM laser power, laser spot position, and geometric and material properties of the cantilever. In the area of nanotechnology, the laser beam deflection method has been widely used in AFMs for detecting the cantilever’s deflection and resonance frequency. The laser deflection method consists of reflecting a laser beam off of an AFM cantilever onto a photo diode, which is converted to a voltage signal. Deflection of the cantilever results in a change in the laser reflection angle and a change in voltage signal. The mechanical properties of the cantilever affect the amount of deflection. Although much work has been done on increasing the sensitivity of the AFM, little work has been done on investigating the thermal effect of the laser-cantilever interaction. We observe that laser-induced thermal expansions in the AFM cantilever are measureable. Our simulated results suggest that both the laser power and spot positions significantly change the resonant response of the cantilevers. The resonance response is critical for the AFM tapping mode. In considering various laser powers, we observe that as we increase the power, the average temperature of the beam increases, which causes a decrease in resonance frequency. In considering various laser reflection spot positions, we find that as the laser spot moves away from the clamped end of the cantilever, the dissipation to the sample which is 6 m below the cantilever tip decreases, causing an increase in temperature but decrease in material softening. The results of our models are close to the experimental results with a relative error of 0.1%.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.

A Study of the Photoelectric Effect Caused by a Laser Beam Used in a Beam Bounce Technique in a C-AFM System

2008 ◽  
Author(s):  
Hung-Sung Lin ◽  
Mong-Sheng Wu
Keyword(s):  
Laser Beam ◽  
Failure Analysis ◽  
Atomic Force Microscope ◽  
Photoelectric Effect ◽  
Scanning Probe ◽  
Nanometer Scale ◽  
Electrical Characteristics ◽  
Atomic Force ◽  
Probe Microscope ◽  
Probe Head

Abstract The use of a scanning probe microscope (SPM), such as a conductive atomic force microscope (C-AFM) has been widely reported as a method of failure analysis in nanometer scale science and technology [1-6]. A beam bounce technique is usually used to enable the probe head to measure extremely small movements of the cantilever as it is moved across the surface of the sample. However, the laser beam used for a beam bounce also gives rise to the photoelectric effect while we are measuring the electrical characteristics of a device, such as a pn junction. In this paper, the photocurrent for a device caused by photon illumination was quantitatively evaluated. In addition, this paper also presents an example of an application of the C-AFM as a tool for the failure analysis of trap defects by taking advantage of the photoelectric effect.

Adhesion and Friction Coupling in Atomic Force Microscope-Based Nanopushing

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Fakhreddine Landolsi ◽  
Fathi H. Ghorbel ◽  
James B. Dabney
Keyword(s):  
Numerical Simulations ◽  
Atomic Force Microscope ◽  
Contact Mechanics ◽  
Interaction Model ◽  
Research Interest ◽  
Visual Sensing ◽  
Atomic Force ◽  
Proposed Model ◽  
Theoretical Investigations ◽  
Afm Cantilever

The use of the atomic force microscope (AFM) as a tool to manipulate matter at the nanoscale has received a large amount of research interest in the last decade. Experimental and theoretical investigations have showed that the AFM cantilever can be used to push, cut, or pull nanosamples. However, AFM-based nanomanipulation suffers a lack of repeatability and controllability because of the complex mechanics in tip-sample interactions and the limitations in AFM visual sensing capabilities. In this paper, we will investigate the effects of the tip-sample interactions on nanopushing manipulation. We propose the use of an interaction model based on the Maugis–Dugdale contact mechanics. The efficacy of the proposed model to reproduce experimental observations is demonstrated via numerical simulations. In addition, the coupling between adhesion and friction at the nanoscale is analyzed.

Simulation of Drilling Micro-Hole by a Dual CO2 Laser Beam Irradiated Sticking Plaster

2012 ◽  
Vol 203 ◽  
pp. 519-522
Author(s):  
Zhi Ming Rao ◽  
Xian Bo Xiao ◽  
Zhi Fang He
Keyword(s):  
Laser Beam ◽  
Co2 Laser ◽  
Laser Power ◽  
Laser Spot ◽  
Beam Power ◽  
Analysis Software ◽  
Element Analysis ◽  
Spot Diameter ◽  
Micro Hole ◽  
Laser Spot Diameter

We explore a simulation model of drilling micro-hole in sticking plaster heated with a dual CO2 laser beam. This paper applied numerical simulation of temperature by using finite element analysis software Ansys to study a model of drilling on sticking plaster. A dual CO2 laser spot sizes ranged from 0.15 to 0.2mm radius with axial irradiance power levels of 50-100w. For temperatures above 450°C, sticking plaster would be vaporized. The size of ventilation holes changed with beam power and laser spot diameter. The width of the hole is increases with the increasing laser diameter and with the increasing laser power. These results can guide to laser drilling experiments.

scholarly journals False Engagements in AFM

1999 ◽  
Vol 7 (2) ◽  
pp. 26-27
Author(s):  
Chetan Dandavate
Keyword(s):  
Laser Beam ◽  
Atomic Force Microscope ◽  
Contact Force ◽  
Feedback Circuit ◽  
Contact Mode ◽  
Voltage Difference ◽  
Atomic Force ◽  
Photo Detectors

In scanning microscopes, like the Atomic Force Microscope (AFM), used in contact mode, scanning begins with engaging the tip with the sample at some contact force, which can be adjusted by the setpoint* (this is common to Digital Instruments' AFMs). It may differ for other brands. For a system that detects the motion of the cantilever with a laser beam, the setpoint basically gives an idea of the voltage difference between the top and bottom photo detectors, When the tip comes into contact, the feedback circuit adjusts the tip deflection according to the required contact force, This is the method commonly followed for the constant deflection method.

DMCMN: Experimental/Analytical Evaluation of the Effect of Tip Mass on Atomic Force Microscope Cantilever Calibration

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Matthew S. Allen ◽  
Hartono Sumali ◽  
Peter C. Penegor
Keyword(s):  
Atomic Force Microscope ◽  
Fundamental Mode ◽  
Spring Constant ◽  
Mode Shapes ◽  
Contact Mode ◽  
Modified Method ◽  
Atomic Force ◽  
Afm Cantilever ◽  
Cantilever Probes ◽  
Tip Mass

Quantitative studies of material properties and interfaces using the atomic force microscope (AFM) have important applications in engineering, biotechnology, and chemistry. Contrary to what the name suggests, the AFM actually measures the displacement of a microscale probe, so one must determine the stiffness of the probe to find the force exerted on a sample. Numerous methods have been proposed for determining the spring constant of AFM cantilever probes, yet most neglect the mass of the probe tip. This work explores the effect of the tip mass on AFM calibration using the method of Sader (1995, “Method for the Calibration of Atomic Force Microscope Cantilevers,” Rev. Sci. Instrum., 66, pp. 3789) and extends that method to account for a massive, rigid tip. One can use this modified method to estimate the spring constant of a cantilever from the measured natural frequency and Q-factor for any mode of the probe. This may be helpful when the fundamental mode is difficult to measure or to check for inaccuracies in the calibration obtained with the fundamental mode. The error analysis presented here shows that if the tip is not considered, then the error in the static stiffness is roughly of the same order as the ratio of the tip’s mass to the cantilever beam’s. The area density of the AFM probe is also misestimated if the tip mass is not accounted for, although the trends are different. The model presented here can be used to identify the mass of a probe tip from measurements of the natural frequencies of the probe. These concepts are applied to six low spring-constant, contact-mode AFM cantilevers, and the results suggest that some of the probes are well modeled by an Euler–Bernoulli beam with a constant cross section and a rigid tip, while others are not. One probe is examined in detail, using scanning electron microscopy to quantify the size of the tip and the thickness uniformity of the probe, and laser Doppler vibrometry is used to measure the first four mode shapes. The results suggest that this probe’s thickness is significantly nonuniform, so the models upon which dynamic calibration is based may not be appropriate for this probe.

Measuring intermolecular binding forces with the Atomic-Force Microscope: The magnetic jump method

1994 ◽  
Vol 52 ◽  
pp. 1054-1055
Author(s):  
J. H. Hoh ◽  
P. E. Hillner ◽  
P. K. Hansma
Keyword(s):  
Bond Strength ◽  
Atomic Force Microscope ◽  
Interaction Force ◽  
Intermolecular Forces ◽  
Atomic Force ◽  
Novel Approach ◽  
Binding Forces ◽  
Afm Cantilever ◽  
Paramagnetic Beads ◽  
Direct Readout

The atomic-force microscope (AFM) can measure forces between atoms and molecules with a sensitivity of <10−12 N. By coating the AFM tip with specific molecules the types of interactions that can be examined will be greatly extended. Recently tips with biotin attached have been used to probe surfaces coated with avidin or streptavidin, to measure the respective bond strength.We have developed a novel approach to measuring intermolecular forces with the AFM that employs paramagnetic beads coated with one of the molecules to be studied. Beads are incubated with a surface coated with the second molecule, and allowed to form a specific bond. A small magnet glued to an AFM cantilever is then advanced toward the bead until the bond with between the two molecules breaks and the bead “jumps” to the magnet. The deflection of the cantilever provides a direct readout of the interaction force at the “jump,” and thereby a measure of the bond strength.

Characterization of Heated Atomic Force Microscope Cantilevers in Air and Vacuum

2005 ◽  
Author(s):  
Jungchul Lee ◽  
Tanya L. Wright ◽  
Mark Abel ◽  
Erik Sunden ◽  
Alexei Marchenkov ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Single Crystal Silicon ◽  
Silicon On Insulator ◽  
Thermal Coupling ◽  
Electrical Measurements ◽  
Crystal Silicon ◽  
Laser Raman ◽  
Atomic Force ◽  
Afm Cantilever

This paper presents characterization of heated atomic force microscope (AFM) cantilevers in air and helium, both at atmospheric pressure and in a partially evacuated environment. The cantilevers are made of doped single-crystal silicon using a standard silicon-on-insulator cantilever fabrication process. The electrical measurements show the link between the cantilever temperature-dependant electrical characteristics, electrical resistive heating, and thermal properties of the heated AFM cantilever and its surroundings. Laser Raman thermometry measures temperature along the cantilever with resolution near 1 μm and 4°C. By modulating the gaseous environment surrounding the cantilever, it is possible to estimate the microscale thermal coupling between the cantilever and its environment. This work seeks to improve the calibration and design of heated AFM cantilevers.

scholarly journals Putting a Sphere on an Atomic Force Microscope Cantilever Tip

1997 ◽  
Vol 5 (10) ◽  
pp. 6-6 ◽  
Author(s):  
Stefan Zauscher
Keyword(s):  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Van Der Waals ◽  
Great Precision ◽  
Atomic Force Microscope Cantilever ◽  
Quantitative Measurements ◽  
Atomic Force ◽  
Afm Cantilever ◽  
Repulsive Forces ◽  
Force Microscope Cantilever

Atomic Force Microscopes (AFM) can measure the force between a surface and the tip of a cantilever as a junction of separation with great precision. For example, van der Waals type forces and electrostatic repulsive forces can easily be measured in aqueous solutions using an AFM. The complex, pyramidal shape of the typical AFM cantilever is, however, not well suited for quantitative measurements. It is thus desirable to attach particles of known geometry (usually spheres) to the tip of a cantilever.

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