Lead Disulfide Microcrystals Atomic force microscopy (AFM) image
of lead disulfide microcrystals grown on a silicon oxide surface
patterned by the AFM using "Dip-pen Nanolithography" (DPN). The
field of view is 11.6 µm across, and the hexagonal crystallites
are about 60 nm high. DPN was used to write a 5 µm x 5 µm
chemically-reactive region on the wafer, which was then soaked
in lead acetate and exposed to H2S gas. Microcrystals
selectively grew starting from the patterned area. S. E. Kooi,
L. A. Baker, P. E. Sheehan, and L. J. Whitman. Image courtesy:
Dr. L. J. Whitman, Naval Research Laboratory.