  We demonstrate solution processable large area field effect transistors
(FETs) from aligned arrays of carbon nanotubes (CNTs). Commercially available,
surfactant free CNTs suspended in aqueous solution were aligned between source
and drain electrodes using ac dielectrophoresis technique. After removing the
metallic nanotubes using electrical breakdown, the devices displayed p-type
behavior with on-off ratios up to ~ 2X10^4. The measured field effect
mobilities are as high as 123 cm2/Vs, which is three orders of magnitude higher
than typical solution processed organic FET devices.
