Transport properties of a dna-conjugated single-wall carbon nanotube field-effect transistor

We performed electrical transport measurements on a DNA-conjugated single-wall carbon nanotube (SWCNT) field-effect transistor (FET) at various temperatures (Ts). At T = 300 K, the gate action of the SWCNT FET clearly exhibited n-type behavior, while the bare SWCNT FET showed usual p-type characteristics. The value of the drain current measured from the DNA-conjugated SWCNT FET decreased rapidly with the decrease of T. We fit the T-dependence of the DNA-conjugated SWCNT FET with a simple back-to-back Schottky diode model and found a slight decrease of B with decreasing T. A possible explanation for the type conversion is the chemical modification of the CNT surface as a result of the conjugation process.