Growth of Carbon Nanotubes:  A Combinatorial Method To Study the Effects of Catalysts and Underlayers

With their interesting electrical, structural, and physical properties, carbon nanotubes (CNTs) are envisioned to impact future nanoelectronics, nanosensors, and nanophotonics. Current research and development efforts in the growth of CNTs rely on the time-consuming one-parameter-at-a-time approach, whereby marginal variations in growth conditions from run-to-run experiments could result in substantially different outcomes. Here we report a highly efficient combinatorial approach to study the effects of catalysts and underlying metals for the generation of a comprehensive discovery library of CNTs. Shadow masking and sequential ion-beam deposition are used to construct an ensemble of catalysts and underlying metals on a generic addressable platform, whereby upon chemical vapor deposition, the CNT library can be assayed efficiently and conveniently to reveal a host of interesting phenomena. The approach could, in principle, be adapted and used for combinatorial investigations of other nanostructures.