Nanoporous silicon nanowire field effect transistor sensors for PH sensing

초록

Nanoporous silicon nanowires (NPSiNWs) with lengths of a few tens of nanometers were synthesized by electroless etching of crystalline silicon in HF-based electrolyte. Next, field effect transistors (FETs) were assembled to be used as a biosensor. The electrical properties of the NPSiNW FET such as drain current-drain voltage (ID-VD) and drain current-gate voltage (ID-VG) curves were obtained using the NPSiNW FET sensor curves under a dry condition. The ability of the NPSiNW FET sensors to detect species in liquid solutions was also demonstrated for the case of PH sensing. Measurements of the conductance as a function of PH exhibited two different response regimes. The PH-dependent changes in conductance were in excellent agreement with previous measurements of the PH-dependent surface charge density derived from silica. Our results indicate that the sensitivity of the NPSiNW FET sensor are higher than that of simple NW FET sensors.