Hysteretic transfer characteristics of double-walled and single-walled carbon nanotube field-effect transistors

In both double-walled carbon nanotube field-effect transistors (DWCNT-FETs) and single-walled carbon nanotube field-effect transistors (SWCNT-FETs), clockwise hysteretic transfer characteristics are observed. These characteristics can be attributed to mobile ions or charged clusters in surfactant layers around the tube channels. Compared with SWCNT-FETs, more significant surfactant influences on the transfer characteristics are observed in DWCNT-FETs due to superior surfactant adsorption properties of double-walled carbon nanotubes. Our findings suggest that not only water molecules but also the surfactants play critical roles in dominating the hystereses, especially when the carbon nanotubes are double walled. (c) 2007 American Institute of Physics.