Sensing mechanism of metal-decorated single-walled carbon nanotube field effect transistor sensors

We investigate the sensing mechanism underlying metaldecorated single-walled carbon nanotube field effect transistor (SWNT-FET) sensors. Upon lowering the temperature, two types of periodic oscillations appeared in the I-V_g characteristics of Ni-decorated SWNT-FETs, specifically, oscillations with a smaller period superimposed (beating) on larger oscillations. These oscillations may have originated from charging of the Ni nanoparticles. This behavior is consistent with a system of multiple quantum dots that are resistively coupled via the SWNT, in which charges generated through biomolecular interactions can be transferred from the metal nanoparticles to the SWNTs without delay.