Figure 4. Three examples of dip-pen nanolithography. (a) In thermal DPN, an atomic
force microscope’s cantilever is coated with a solid ink that, when heated, liquefies and is
deposited on the surface. (b) In electro-pen nanolithography, the tip simultaneously deposits
the ink (green) and changes the surface chemistry to allow the ink to adhere to the surface.
(c) In the nano fountain pen, a microchannel guides the ink from the reservoir to the tip,
where it flows into the substrate though a water meniscus.