Veeco Dimension 3100, Manual

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Fluid Imaging
Basic Principles
Rev. D Dimension 3100 Manual 151
10.1 Basic Principles
Attractive forces due to surface tension effects are eliminated when imaging samples under fluid.
This enables the sample surface to be imaged with minimal cantilever tip force—a decided
advantage when imaging biological specimens and delicate materials. The procedure for observing
samples under fluid is similar to that for observation in air; however, special hardware is utilized to
contain the fluid. In addition, minor adjustments must be made to correct for refractive effects as the
laser beam transits air-fluid boundaries.
This chapter assumes familiarity with standard operation of the Dimension 3100 AFM in air. If you
are not familiar with air operation of the AFM in Contact Mode, please follow the procedures
outlined in
Chapter 8 before attempting to operate the AFM under fluid. If you are not familiar with
air operation of TappingMode, refer to Chapter 9 .
10.1.1 Acknowledgments
Veeco appreciates the following individuals’ assistance with the following sections: Monika Fritz,
Manfred Radmacher, Magdalena Benzanilla, Helen G. Hansma, Jan H. Ho, Craig B. Prater.
10.2 Fluid Operation Hardware
10.2.1 Fluid Tip Holder
The Dimension 3100 can be equipped with an optional tip holder that permits operation under fluid
(see
Figure 10.2a ). The fluid tip holder interchanges with the standard tip holder quickly and easily.
The fluid tip holder consists of a small glass assembly with a wire clip for holding an AFM
cantilever substrate. The glass surfaces provide a flat, beveled interface so that the AFM laser beam
may pass into the fluid without being distorted by an unstable fluid surface. The four sockets
located on the top of the fluid tip holder are used to attach the tip holder to the four pins at the end
of the scanner tube.
Use the fluid tip holder in an open environment where the holder is dipped into a user-supplied fluid
container (or into a drop of fluid on larger samples). A method for mounting samples for fluid
operation is illustrated in
Figure 10.3a in Section 10.3 .