Page 52 - Principles and Applications of NanoMEMS Physics

38 Chapter 1

accomplished by two techniques, namely, exploiting AFM to push particles,
and DIP-Pen lithography.

1.2.3.6.1 AFM-based Nanomanipulation

In this technique, an oscillating AFM tip is brought close to a particle
until, as a result of jump-to-contact, the oscillation amplitude goes to zero.
The AFM approaches the nanoparticle via a fast X-Y scanning oscillation, in
a plane perpendicular to the desired pushing direction, z, see Figure 1-34.
Once contact of the AFM with the nanoparticle is established, motion
proceeds in the z-direction at a slow scan rate.

Trajectory of Tip in X,Y
Trajectory of Tip in X,Y

Pushing Direction
Pushing Direction
Fast Scan
Fast Scan

Slow Scan
Slow Scan

Figure 1-34. Pushing a nanoparticle with AFM. (After [49].)

1.2.3.6.2 DIP-Pen Lithography

In this technique, developed by Mirkin’s group [50], see Fig. 1-35, and

AFM Tip

Writing
Direction
Molecular
Transport
Water
Meniscus

Solid Substrate

Figure 1-35. Close-up of inked AFM tip as molecules flow down the tip via water meniscus.
(After [50].)