Theoretical investigation of silicon nanowire pH sensor

In this paper, Si nanowire (NW) sensor in pH detection is presented. The conductance of device is analytically obtained and demonstrated the conductance increases with reducing the oxide thickness. To calculate the electrical conductance of sensor, the diffusion-drift model and nonlinear Poisson-Boltzmann equation are used. To improve the conductance a Si NW sensor with nanoscale side gate voltage is presented and its conductance is theoretically achieved. It is shown the conductance and consequently sensor sensitivity can be enhanced by adding suitable side gate voltage. Finally this effect is compared to the almost similar fabricated structure in literature which has a wire with rectangular cross section.