Reducing electrical resistance in single-walled carbon nanotube networks: effect of the location of metal contacts and low-temperature annealing

Density control during the formation of 2-D networks of unsorted single-walled carbon nanotubes (SWNTs) allows their macroscopic electrical properties to be tuned from semiconductive to metallic conduction, even though they are composed of 1/3 metallic and 2/3 semiconductive nanotubes.  This allows their use in numerous new materials applications.  However, the resistance of such thin-films is generally high, dominated by the effects of inter-SWNT tunneling junctions, metal/SWNT contacts, sidewall defects, and the presence of residual dopants.  Initial studies have provided insight into the relative contributions of each of these contributors to the overall performance of SWNT networks in field-effect transistors.  Additionally, the effect of the structure of the metal/SWNT contact, and annealing temperature were investigated.  It was found that depositing the network on top of prefabricated metal contacts allowed up to a 13-fold reduction in resistance, much greater reproducibility in inter-network conductivity, and up to a 2-fold increase in on/off ratio.

Doc.: http://link.springer.com/content/pdf/10.1007%2Fs10853-011-6161-9.pdf

Zhang, Q., Vivhvhulada, P., B Shivareddy, S., & D. Lay, M. (2012). Density control during the formation of 2-D networks of unsorted single-walled carbon nanotubes (SWNTs) allows their macroscopic electrical properties to be tuned from semiconductive to metallic conduction, even though they are composed of 1/3 metallic an. J Mater Sci, 3233-3240