“…The average emission characteristic time remains about constant, while the average capture characteristic time demonstrates a strong dependence on the liquid-gate voltage applied. It should be noted that such behavior of RTS time constants is typical for liquid-gated nanowire-based FET devices 22 , 32 , 36 . Figure 4 RTS noise characteristics.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
confidence: 80%
“…For example, in Ref. 32 we measured and analyzed 40 s long RTS time traces to detect very low concentrations of target biomolecules. As a result, enhanced sensitivity was achieved and demonstrated for the single-trap phenomena approach.…”
Section: Discussionmentioning
confidence: 99%
“…The usual signal in transistor-based biosensors is a shift of drain current, and current fluctuations are noise. In contrast, we define the signal in single-trap-based biosensors 21 , 22 , 32 as trap occupancy probability . To calculate the g-factor noise (fluctuations in time) considering two-level RTS time trace, one can extract over a given window directly from the distribution of the voltage fluctuations (see Fig.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
confidence: 99%
“…Figure 4 a shows the two-level drain current fluctuations measured for the 100 nm wide and 100 nm long liquid-gated Si NW FET. The device was fabricated using a previously reported protocol 32 . A brief description of the main fabrication steps is also presented in Supporting information (SI) of this work.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
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
2
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. In particular, we show that, when a single trap is active near the conductive channel, the noise can be suppressed even beyond the thermal limit by monitoring the trap occupancy probability in an approach analog to the stochastic resonance effect used in biological systems.
“…The average emission characteristic time remains about constant, while the average capture characteristic time demonstrates a strong dependence on the liquid-gate voltage applied. It should be noted that such behavior of RTS time constants is typical for liquid-gated nanowire-based FET devices 22 , 32 , 36 . Figure 4 RTS noise characteristics.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
confidence: 80%
“…For example, in Ref. 32 we measured and analyzed 40 s long RTS time traces to detect very low concentrations of target biomolecules. As a result, enhanced sensitivity was achieved and demonstrated for the single-trap phenomena approach.…”
Section: Discussionmentioning
confidence: 99%
“…The usual signal in transistor-based biosensors is a shift of drain current, and current fluctuations are noise. In contrast, we define the signal in single-trap-based biosensors 21 , 22 , 32 as trap occupancy probability . To calculate the g-factor noise (fluctuations in time) considering two-level RTS time trace, one can extract over a given window directly from the distribution of the voltage fluctuations (see Fig.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
confidence: 99%
“…Figure 4 a shows the two-level drain current fluctuations measured for the 100 nm wide and 100 nm long liquid-gated Si NW FET. The device was fabricated using a previously reported protocol 32 . A brief description of the main fabrication steps is also presented in Supporting information (SI) of this work.…”
Section: Noise Suppression Beyond the Thermal Limitmentioning
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
2
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. In particular, we show that, when a single trap is active near the conductive channel, the noise can be suppressed even beyond the thermal limit by monitoring the trap occupancy probability in an approach analog to the stochastic resonance effect used in biological systems.
“…To target the Aβ-40 (amyloid beta-40) sequence, ssDNA aptamer was designed, synthesized, and immobilized on silicon (Si) nanowire (NW) FETs altered with a thin layer of SiO 2 . The binding of Aβ peptides of different concentrations in the buffer solution to the sensors’ surface was in the range from 0.1 pg/ml to 10 μg/ml [ 80 ]. Fig.…”
Section: Selective Adhesion On Fet For Biosensing Applicationsmentioning
The use of field-Effect-Transistor (FET) type biosensing arrangements has been highlighted by researchers in the field of early biomarker detection and drug screening. Their non-metalized gate dielectrics that are exposed to an electrolyte solution cover the semiconductor material and actively transduce the biological changes on the surface. The efficiency of these novel devices in detecting different biomolecular analytes in a real-time, highly precise, specific, and label-free manner has been validated by numerous research studies. Considerable progress has been attained in designing FET devices, especially for biomedical diagnosis and cell-based assays in the past few decades. The exceptional electronic properties, compactness, and scalability of these novel tools are very desirable for designing rapid, label-free, and mass detection of biomolecules. With the incorporation of nanotechnology, the performance of biosensors based on FET boosts significantly, particularly, employment of nanomaterials such as graphene, metal nanoparticles, single and multi-walled carbon nanotubes, nanorods, and nanowires. Besides, their commercial availability, and high-quality production on a large-scale, turn them to be one of the most preferred sensing and screening platforms. This review presents the basic structural setup and working principle of different types of FET devices. We also focused on the latest progression regarding the use of FET biosensors for the recognition of viruses such as, recently emerged COVID-19, Influenza, Hepatitis B Virus, protein biomarkers, nucleic acids, bacteria, cells, and various ions. Additionally, an outline of the development of FET sensors for investigations related to drug development and the cellular investigation is also presented. Some technical strategies for enhancing the sensitivity and selectivity of detection in these devices are addressed as well. However, there are still certain challenges which are remained unaddressed concerning the performance and clinical use of transistor-based point-of-care (POC) instruments; accordingly, expectations about their future improvement for biosensing and cellular studies are argued at the end of this review.
Biomarkers are primary indicators for precise diagnosis and treatment. The early identification of health biomarkers has been sustained by the evolutionary success in sensor technologies. Among them, graphene field-effect transistor (GFET) biosensors have exhibited major advantages such as an ultrashort response time, high sensitivity, easy operation, capability of integration, and label-free detection. Owing to the atomic thickness, graphene restricts charge carrier flow merely at the material surface and responds to foreign stimuli directly, leading to effective signal acquisition and transmission. Here, this review summarizes the latest advances in GFET biosensors in a comprehensive manner that contains the device design, working principle, surface functionalization, and proof-of-concept applications. It provides a comprehensive survey of GFET biosensors with regard to biomarker analysis at the single-device level and integrated prototypes that include wearable sensors, biomimetic systems, healthcare electronics, and diagnostic platforms. Moreover, there is discussion on the long-standing research efforts and outlook for the future development of GFET sensor systems from lab to fab.
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