Noise suppression beyond the thermal limit with nanotransistor biosensors.

Transistor biosensors are mass-fabrication-compatible devices of interest for point of care diagnosis as well as molecular interaction studies. While the actual transistor gates in processors reach the sub-10 nm range for optimum integration and power consumption, studies on design rules for the signal-to-noise ratio (S/N) optimization in transistor-based biosensors have been so far restricted to 1 µm device gate area, a range where the discrete nature of the defects can be neglected. In this study, which combines experiments and theoretical analysis at both numerical and analytical levels, we extend such investigation to the nanometer range and highlight the effect of doping type as well as the noise suppression opportunities offered at this scale.

Towards pharmacological treatment screening of cardiomyocyte cells using Si nanowire FETs.

Silicon nanowires (Si NWs) are the most promising candidates for recording biological signals due to improved interfacing properties with cells and the possibility of high-speed transduction of biochemical signals into detectable electrical responses. The recording of extracellular action potentials (APs) from cardiac cells is important for fundamental studies of AP propagation features reflecting cell activity and the influence of pharmacological substances on the signal. We applied a novel approach of using fabricated Si NW field-effect transistors (FETs) in combination with fluorescent marker techniques to evaluate the functional activity of cardiac cells.

Noise spectroscopy to study the 1D electron transport properties in InAs nanowires.

InAs nanowires (NWs) are recognized as a key material due to their unique transport properties. Despite remarkable progress in designing InAs NW device structures, there are still open questions on device variability. Here, we demonstrate that noise spectroscopy allows us to study not only the parameters of traps, but also to shed light on quantum transport in NW structures.

Liquid-Gated Two-Layer Silicon Nanowire FETs: Evidence of Controlling Single-Trap Dynamic Processes.

We fabricate two-layer (TL) silicon nanowires (NW) field-effect transistors (FETs) with a liquid gate. The NW devices show advanced characteristics, which reflect reliable single-electron phenomena. A strong modulation effect of channel conductivity with effectively tuned parameters is revealed.

Photoconductivity, pH Sensitivity, Noise, and Channel Length Effects in Si Nanowire FET Sensors.

Silicon nanowire (NW) field-effect transistor (FET) sensors of various lengths were fabricated. Transport properties of Si NW FET sensors were investigated involving noise spectroscopy and current-voltage (I-V) characterization. The static I-V dependencies demonstrate the high quality of fabricated silicon FETs without leakage current.

Origin of noise in liquid-gated Si nanowire troponin biosensors.

Liquid-gated Si nanowire field-effect transistor (FET) biosensors are fabricated using a complementary metal-oxide-semiconductor-compatible top-down approach. The transport and noise properties of the devices reflect the high performance of the FET structures, which allows label-free detection of cardiac troponin I (cTnI) molecules. Moreover, after removing the troponin antigens the structures demonstrate the same characteristics as before cTnI detection, indicating the reusable operation of biosensors.

Effect of Gamma Irradiation on Dynamics of Charge Exchange Processes between Single Trap and Nanowire Channel.

In the present study, transport properties and single trap phenomena in silicon nanowire (NW) field-effect transistors (FETs) are reported. The dynamic behavior of drain current in NW FETs studied before and after gamma radiation treatment deviates from the predictions of the Shockley-Read-Hall model and is explained by the concept taking into account an additional energy barrier in the accumulation regime. It is revealed that dynamics of charge exchange processes between single trap and nanowire channel strongly depend on gamma radiation treatment.

Electronic edge-state and space-charge phenomena in long GaN nanowires and nanoribbons.

We studied space-charge-distribution phenomena in planar GaN nanowires and nanoribbons (NRs). The results obtained at low voltages demonstrate that the electron concentration changes not only at the edges of the NR, but also in the middle part of the NR. The effect is stronger with decreasing NR width.

[Diagnosis of disorders of the fetal status using computer-assisted cardiotocography].

The diagnostic system of cardiotocogram analysis in real time scale is described, and the diagnostic data of computer cardiotocography in various periods of os dilatation presented. Analysis of correlations and regressions of the parameters reflecting disorders of the fetal status has shown that the most significant parameter in the diagnosis of fetal status abnormalities is variability from beat to beat.

[Medico-technical aspects of the determination of the hematocrit number based on the electric conductivity of blood].

The prospects of hematocrit value determination from blood electroconduction for clinical purposes were determined. To improve the hematocrit value validity, which is defined from electrical blood resistance (ER) was offered more accurate approximated function. The methods and results of experimental investigations related to the determination of the approximated function are described.