pH dependent electrical characteristic of bottom-up synthesized silicon nanowire FETs with DDT passivation

Electrical characteristic of bottom-up synthesized silicon nanowire FETs is studied for possible pH sensing device applications. Dodecanethiol (DDT) molecules are used for the passivation of gold electrodes. This passivation changes the drain current level and the threshold voltage of the transistor, which could be due to the reaction of native oxide of the silicon surface with DDT molecules. The DDT passivation efficiently blocks the direct current through the electrolyte solution and the transistor is shown to respond to the change of pH.