Influence of Conductivity and Dielectric Constant of Water–Dioxane Mixtures on the Electrical Response of SiNW-Based FETs

Abstract

In this study, we report on the electrical response of top-down, p-type silicon nanowire field-effect transistors exposed to water and mixtures of water and dioxane. First, the capacitive coupling of the back gate and the liquid gate via an Ag/AgCl electrode were compared in water. It was found that for liquid gating smaller potentials are needed to obtain similar responses of the nanowire compared to back gating. In the case of back gating, the applied potential couples through the buried oxide layer, indicating that the associated capacitance dominates all other capacitances involved during this mode of operation. Next, the devices were exposed to mixtures of water and dioxane to study the effect of these mixtures on the device characteristics, including the threshold voltage (VT). The VT dependency on the mixture composition was found to be related to the decreased dissociation of the surface silanol groups and the conductivity of the mixture used. This latter was confirmed by experiments with constant conductivity and varying water–dioxane mixtures.

Ionophore-Containing Siloprene Membranes: Direct Comparison between Conventional Ion-Selective Electrodes and Silicon Nanowire-Based Field-Effect Transistors

“…On the contrary, the response of SiO 2 -coated SiNW-FETs to both Na + and K + reported by Park et al was found to be nonlinear . It is noted that in these studies, the electrical conductivity was not kept constant, which affects the response . In our case, however, the electrical conductivity of the two solutions is nearly the same.…”

“…SiNW-FETs were produced as reported previously. , Briefly, the SiNWs (p-doped at a concentration of 10 16 cm –3 ) are 3 μm in length, 300 nm in width, and 40 nm in height and were covered with a silicon dioxide gate oxide with a thickness of 8 nm. The thickness of the buried oxide (BOX) layer is 300 nm.…”

Metal–Organic Polyhedra-Coated Si Nanowires for the Sensitive Detection of Trace Explosives

“…To assess the sensing efficacy of our Cu-MOP-modified nanodevice, explosive-containing solutions with different concentrations ranging from the ppb to ppm level were delivered to the sensor chip through a homemade fluid delivery system. 26 To avoid the hydrolysis or desorption of Cu-MOP by water, absolute ethanol was chosen as a solvent. The dependence of the drain−source current (I ds ) on the gate voltage (V g ) at a fixed drain−source voltage (V ds ) for bare, PETES-, and Cu-MOP-modified SiNW devices in the absolute ethanol environment is shown in Figure 2c (see Supporting Information, Section 1.6 for details on the electrical characterization).…”

“…Before connecting the chip to the semiconductor characterization system, the modified chips were wire-bonded using conductive glue and Al wires (25 μm in diameter) to the chip holder (Figure b, see also Supporting Information, Section 1.5). To assess the sensing efficacy of our Cu-MOP-modified nanodevice, explosive-containing solutions with different concentrations ranging from the ppb to ppm level were delivered to the sensor chip through a homemade fluid delivery system . To avoid the hydrolysis or desorption of Cu-MOP by water, absolute ethanol was chosen as a solvent.…”

A new approach to design an efficient micropost array for enhanced direct-current insulator-based dielectrophoretic trapping

“…Afterwards, a 4-µl suspension (2.5% aqueous suspension) of polystyrene red dyed beads with a diameter of 6 μm and a concentration of 2.10 × 10^8 particles/ml (Warrington, Pennsylvania USA) are diluted in 16-µl of de-ionized water (ε r =80.1; ρ=~20 kΩcm) [29] with a resulting PH of 6.5 and the sample is introduced in the channel inlet.…”