PhD Orals - Ali Fatih Sarioglu, July 24, 2009, 3:45 pm, Packard 101

Fatih Sarioglu sarioglu at stanford.edu
Fri Jul 24 07:22:16 PDT 2009


Speaker: Ali Fatih Sarioglu, sarioglu at stanford.edu 
<mailto:sarioglu at stanford.edu>
Title: Time-resolved Tapping-mode Atomic Force Microscopy
Date: Friday, July 24, 2009
Time: 3:45 pm (Refreshments at 3:30 pm)
Location: Packard Room 101

Abstract:

There is an increasing interest in the use of atomic force microscopy 
(AFM) for quantitative mapping of material specific surface properties. 
However, methods that have been developed for local stiffness 
measurements generally suffer from low operational speeds and they apply 
large forces to the surface limiting their resolution and use on soft 
materials such as polymers and biological samples. On the other hand, 
tapping-mode AFM, which is well suited to soft materials due to its 
gentle interaction with the surface, cannot be used to recover 
information on the tip-sample interaction (and hence, on the material 
properties) due to limited bandwidth of the AFM probe.

In this talk, a technique for rapid quantitative material 
characterization with nanoscale spatial resolution will be introduced. 
This technique is based on time-resolved measurement of tip-sample 
interaction forces during tapping-mode AFM imaging by a special 
micromachined AFM probe. In this probe, a high-bandwidth interferometric 
force sensor at the end of the cantilever is coupled to the tip motion 
and is used to resolve tip-sample interaction forces with high 
sensitivity and temporal resolution. Combined with a real-time signal 
processing software that we developed, these probes provide quantitative 
maps of peak interaction forces and elastic properties simultaneously 
with conventional AFM data. High-contrast compositional mapping, 
quantitative peak force imaging and quantitative material 
characterization by mapping surface Young's modulus acquired using this 
system will be demonstrated on various samples.



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