Site-specific deposition of gold nanoparticles on SWNTs

A simple strategy was developed to site-specifically deposit gold nanoparticles on single-walled carbon nanotubes (SWNTs) using dip-pen nanolithography (DPN) or electrochemical dip-pen nanolithography (EDPN). As-grown SWNTs on SiQ(x)/Si substrates were directly used without any pretreatment. By adjusting the writing velocity, tip voltage bias, and the times of seeded growth processes, gold nanoparticles with sizes from several nanometers to tens of nanometers could be controllably deposited on SWNTs. E-DPN provided a route for in situ monitoring the deposition of gold nanoparticles. Without any extra processing step in solution, this route resulted in clean gold nanoparticles/SWNT heterostructures. This DPN-based strategy may find potential application for the fabrication of site-defined nanoscaled heterostructures, site-specific microelectrodes on SWNTs, and room-temperature single-electron transistors.