Self-assembled carbon nanotubes for electronic circuit and device applications

Functionalized, self-assembled carbon nanotubes are discussed in relation to electronic devices, circuits, and architectures. A computational approach is described using density functional theory coupled with nonequilibrium Green function theory for modeling the device electrical properties. While most current work has focused on carbon nanotubes used for field-effect transistors, carbon nanotubes connected by molecular linkers can act electronically as resonant tunneling diodes. The addition of resonant tunneling diodes to transistor circuitry allows for greater functionality with fewer devices. The greatest advantage of this for self-assembly is simplified circuit topology. The resonant tunneling operation is demonstrated both theoretically and experimentally for carbon nanotube-L-R-L-carbon nanotube systems in which L is the amide linker and R is either C2H4 or single-strand DNA.