Iron Nanoparticles Derived from Iron-Complexed Polymethylglutarimide To Produce High-Quality Lithographically Defined Single-Walled Carbon Nanotubes A polymer, PMGI, serves as a template to generate uniformly distributed iron nanoparticles with controlled size. These nanoparticles have proven to be excellent catalysts for generating carbon nanotubes (CNTs). The catalyst locations can be defined by a single photolithography step for spatially selective growth of CNTs.