A selective electrochemical approach to carbon nanotube field-effect transistors

Commercial fabrication of field-effect transistors (FETs) using carbon nanotubes has been hindered as all current production procedures yield a mixture of metallic and semiconducting tubes. Herein, we present a generic approach utilizing electrochemistry for selective covalent modification of metallic nanotubes, resulting in exclusive electrical transport through the unmodified semiconducting tubes. Toward this goal, the semiconducting tubes are rendered nonconductive by application of an appropriate gate voltage prior to the electrochemical modification. The FETs fabricated in this manner display good hole mobilities and a ratio approaching 106 between the current in the ON and OFF state.