Fig. 2.

(a) Measurement setup, where a source-drain bias potential is applied and the device is gated through a Ag/AgCl reference electrode inserted in the electrolyte. (b, c) Changes in liquid gate sweeps of ambipolar devices measured during protein adsorption experiments. (b) Example of strong electrostatic gating (adsorption of 185 nM poly-L-lysine on an ambipolar SWNT device). (c) Example of a strong Schottky barrier effect in the case of adsorption of 1 µM horse heart cytochrome-c on a short (40 nm) SWNT device. (Reproduced with permission from Ref. (52), copyright 2008 American Chemical Society).