Title: Photo-Chemically Directed Self-Assembly of Carbon Nanotubes on Surfaces,
Abstract: Transistors incorporating single-wall carbon nanotubes (CNTs) as the channel
material are used in a variety of electronics applications. However, a
competitive CNT-based technology requires the precise placement of CNTs at
predefined locations of a substrate. One promising placement approach is to use
chemical recognition to bind CNTs from solution at the desired locations on a
surface. Producing the chemical pattern on the substrate is challenging. Here
we describe a one-step patterning approach based on a highly photosensitive
surface monolayer. The monolayer contains chromophopric group as light
sensitive body with heteroatoms as high quantum yield photolysis center. As
deposited, the layer will bind CNTs from solution. However, when exposed to
ultraviolet (UV) light with a low dose (60 mJ/cm2) similar to that used for
conventional photoresists, the monolayer cleaves and no longer binds CNTs.
These features allow standard, wafer-scale UV lithography processes to be used
to form a patterned chemical monolayer without the need for complex substrate
patterning or monolayer stamping.