The pH sensor with the poly-Silicon nanowire

In this paper, we demonstrated the dimensional properties of the poly-Si nanowire pH sensor with numerical simulation and fabricated the pH sensor based on the theoretical prediction. According to the simulation results, we found that the width and length of the poly-Si nanowire are critical dimensional factors and the variation of the drain current will be increased as the width increased but decreased as the length increased of the poly-Si nanowire. In addition, the drain current will also affect by the back gate voltage and will increase sharply as the back gate voltage increase. Based on simulation prediction, we fabricated a poly-Si nanowire device for pH measurement within the range of 3 to 11. The sensitivity of the pH sensor is about 0.35 μA/pH.