Noise Spectroscopy Analysis of Ion Behavior in Liquid Gate-All-Around Silicon Nanowire Field-Effect Transistor Biosensors

The transport and noise properties of fabricated, high-performance, gate-all-around silicon liquid-gated nanowire field-effect transistor devices are investigated in different concentrations of MgCl2 solutions. The critical concentration of MgCl2 solution for charge inversion at the solid-liquid interface is verified using noise spectroscopy and confirmed using the capacitance-voltage measurement technique. In this study, it is found that the Hooge parameter (& alpha;H) and the equivalent input noise (SU) can effectively reflect the ion behavior on the surface of the nanowire. Moreover, the noise curves for & alpha;H and SU indicate two turning points at concentrations of 10-4 and 10-1 m for a peak and a valley, respectively. The noise transformation is related to the behavior of ions near the solid-liquid interface in solutions with different MgCl2 concentrations is revealed. The results show that noise spectroscopy is a powerful method for monitoring charge dynamic processes in the research field of biosensors. High-performance gate-all-around Si nanowire field-effect transistor devices are fabricated and studied in different concentrations of MgCl2 solutions. The charge inversion phenomenon is registered at the solid-liquid interface in a concentration of 10-4 m and confirmed by several characteristics. Noise spectroscopy and dimensionless Hooge parameters represent a new approach for characterization of ion dynamic processes and charge inversion effects.image