Gate Field Effect Transistor Research Articles

Highly Sensitive Detection of the Antidepressant Fluoxetine With an Extended Gate Field Effect Transistor

Fluoxetine (FL) is one of the selective serotonin reuptake inhibitors, which is used as an anti-depressant, as well as anti-panic drug. In this work, a sensor for label-free recognition of trace amounts of FL is introduced, which is based on an extended gate field-effect transistor (EGFET). This sensor enables the detection and accurate measurement of FL concentrations over wide dynamic range. The sensing part of the device is a Pt electrode covered by a sensitive polyvinyl chloride (PVC) membrane. The functionalized Pt electrode acting as an extended gate of the EGFET, is connected to the internal gate of a MOSFET transducer. The sensing element of the PVC membrane is the insoluble ion-pair of FL cation and tetraphenylborate anion. The sensor performance for detection of FL was characterized in different ionic strengths of the matrix solution. Then, the sensor capability to operate in physiological phosphate-buffered saline (PBS) was assessed, where the sensor indicated two linear dynamic ranges of its response, with different sensitivities in 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−11</sup> -10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−5</sup> M and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−5</sup> -10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> M ranges. Also the calculated detection limit for the sensor was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.63\times 10^{-12}$ </tex-math></inline-formula> M. Moreover, the selectivity of the sensor was examined and validated in the presence of Citalopram, which is another anti-depressant drug with a similar structure to FL. We proposed a comprehensive analytical mapping of current sensitivity in all working regimes of the EGFET, providing a guide to the design of optimized sensors in any integrated systems of interest. Finally, the sensor was successfully exploited to assay citalopram in its pharmaceutical formulation.

Fabrication and Characterization of nMOS Inverters Utilizing Quantum Dot Gate Field Effect Transistor (QDGFET) for SRAM Device

This paper presents experimental results of nMOS quantum dot gate field effect transistor (QDGFET) based inverter devices for SRAM devices. A three-state inverter device was fabricated and tested with Si/SiO2 quantum dots. The work performed here builds off previous works performed with Si/SiO2 dot-based inverters which used two layers of quantum dots. This research explores multi-state SRAM device operation. A three-state (Si QDs) and a four-state (Si and Ge QDs) inverter are described, and they will allow for multistate logic devices to be utilized in everyday logic chips, which will require less devices to perform the same tasks as conventional devices, double the capacity of the device, and require less power, which will generate less of a thermal footprint. The data of the Half Cell SRAM, comprised of one access transistor and an inverter along with a capacitor, is presented here.

Highly Sensitive and Selective Detection of Diabetic Nephropathy Markers by a Perovskite LaNiO3−x Based Potentiometric Sensor

This work describes the fabrication of efficient biosensors to detect diabetic nephropathy markers (pH, glucose, and creatinine) by constructing a layer-wise sol-gel deposited perovskite LaNiO3−x (LNO) thin-film combined with intermedial annealing (500°C to 700°C). The structural, morphological, and compositional properties of LNO were analyzed by X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The bilayer-coated LNO thin film annealed at 600°C exhibited the highest pH sensitivity of 65.83 mV pH−1 with 99.36% linearity for pH 2 to pH 12, a minimum hysteresis of 0.6 mV, and an almost unvarying drift rate of 2.04 mV h−1 in an extended gate field effect transistor (EGFET). Furthermore, the optimized film was utilized to detect glucose and creatinine by immobilizing different enzymes on the LNO surface. The glucose sensor was able to detect glucose with a sensitivity of 20.5 mV mM−1, whereas the sensitivity of the creatinine sensor was 126.4 mVpCcreatinine −1 for an acceptable linear range, with high selectivity for their respective target molecules. Hence, an LNO-based EGFET sensor can be considered a decisive solicitant for diagnosing diabetic nephropathy.

PH Measurement at Elevated Temperature with Vessel Gate and Oxygen-Terminated Diamond Solution Gate Field Effect Transistors.

Diamond has many appealing properties, including biocompatibility, ease of surface modification, and chemical–physical stability. In this study, the temperature dependence of the pH-sensitivity of a oxygen-terminated boron-doped diamond solution gate FET (C-O BDD SGFET) is reported. The C-O BDD SGFET operated in an electrolyte solution at 95 °C. At 80 °C, the pH sensitivity of C-O BDD SGFET dropped to 4.27 mV/pH. As a result, we succeeded in developing a highly sensitive pH sensing system at −54.6 mV/pH at 80 °C by combining it with a highly pH sensitive stainless-steel vessel.

Power and delay analysis of dielectric modulated dual cavity Junctionless double gate field effect transistor based label-free biosensor

Recently, Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based biosensors have gained immense attraction as a diagnostic tool for point-of-care testing. This paper investigates the current sensitivity, power consumption, and intrinsic delay of the Dual Cavity Junction-less (JL) Double gate MOSFET-based biosensor. Dielectric modulation has been incorporated for label-free biosensing. The impact of neutral and charged biomolecules has been investigated on the current sensitivity, power consumption, and delay. Extensive simulation using SILVACO ATLAS has been done to study the effects. Efficacy of the dual cavity in comparison to the single cavity in JL-MOSFET is demonstrated in terms of better current sensitivity and less power consumption. This work demonstrates the low-power JL-MOSFET-based label-free biosensors for the implementation of cost-efficient and simpler analytical tools for the screening of drugs and biomolecules.

Layer-Dependent Raman Spectroscopy and Electronic Applications of Wide-Bandgap 2D Semiconductor β-ZrNCl.

In recent years, 2D layered semiconductors have received much attention for their potential in next-generation electronics and optoelectronics. Wide-bandgap 2D semiconductors are especially important in the blue and ultraviolet wavelength region, although there are very few 2D materials in this region. Here, monolayer β-type zirconium nitride chloride (β-ZrNCl) is isolated for the first time, which is an air-stable layered material with a bandgap of ≈3.0eV in bulk. Systematical investigation of layer-dependent Raman scattering of ZrNCl from monolayer, bilayer, to bulk reveals a blueshift of its out-of-plane A1g peak at ≈189cm-1 . Importantly, this A1g peak is absent in the monolayer, suggesting that it is a fingerprint to quickly identify the monolayer and for the thickness determination of 2D ZrNCl. The back gate field-effect transistor based on few-layer ZrNCl shows a high on/off ratio of 108 . These results suggest the potential of 2D β-ZrNCl for electronic applications.

Rapid and low-cost, and disposable electrical sensor using an extended gate field-effect transistor for cardiac troponin I detection.

Field effect transistor (FET) biosensor is based on metal oxide field effect transistor that is gated by changes in the surface charges induced the reaction of biomolecules. In most cases of FET biosensor, FET biosensor is not being reused after the reaction; therefore, it is an important concept of investigate the biosensor with simplicity, cheap and reusability. However, the conventional cardiac troponin I (cTnI) sensing technique is inadequate owing to its low sensitivity and high operational time and cost. In this study, we developed a rapid and low-cost, and disposable electrical sensor using an extended gate field-effect transistor (EGFET) to detect cTnI, as a key biomarker for myocardiac infarction. We first investigated pH sensing characteristics according to the pH level, which provided a logarithmically linear sensitivity in the pH sensing buffer solution of approximately 57.9mV/pH. Subsequently, we prepared a cTnI sample and monitored the reaction between cTnI and cTnI antibodies through the changes in the drain current and transfer curves. Our results showed that the EGFET biosensor could successfully detect the cTnI levels as well as the pH with low-cost and rapid detection.

Hydrogel-Coated Gate Field-Effect Transistor for Real-Time and Label-Free Monitoring of β-Amyloid Aggregation and Its Inhibition.

In this paper, we propose a hydrogel-coated gate field-effect transistor (FET) for the real-time and label-free monitoring of β-amyloid (Aβ) aggregation and its inhibition. The hydrogel used in this study is composed of poly tetramethoxysilane (TMOS), in which Aβ monomers are entrapped and then aggregate, and coated on the gate insulator; that is, Aβ aggregation is induced in the vicinity of the sensing surface. With the Aβ hydrogel-coated gate FET, the steplike decrease in the surface potential of the Aβ hydrogel-coated gate electrode is electrically monitored in real time, according to the stepwise aggregation of Aβ monomers to form into fibrils through oligomers and so forth in stages. This is because the capacitance of the Aβ-hydrogel membrane decreases depending on the stage of aggregation; that is, the hydrophobicity of the Aβ-hydrogel membrane increases stepwise depending on the amount of Aβ aggregates. The formation of Aβ fibrils is also confirmed in the measurement solution using a fluorescent dye, thioflavin T, which selectively binds to the Aβ fibrils. Moreover, the addition of daunomycin, an inhibitor of Aβ aggregation, to the measurement solution suppresses the stepwise electrical response of the Aβ hydrogel-coated gate FET. Thus, a platform based on the Aβ hydrogel-coated gate FET is suitable for a simple screening system for inhibitors of Aβ aggregation, which may lead the identification of potential therapeutic agents for Alzheimer's disease.

Analytical Modeling of Sensitivity Parameters Influenced by Practically Feasible Arrangement of Bio-Molecules in Dielectric Modulated FET Biosensor

In this paper, analytical modeling of a Dielectric Modulated Double Gate Field Effect Transistor (DM-DGFET) for biosensing application is presented with extensive data analysis. Firstly, the size of the nanogaps and arrangements of biomolecules in those gaps are optimized with respect to the sensitivity of the above sensor. The optimized DM-DGFET is next analyzed on the basis of its modeling and simulation. This paper addresses novel issues arising from arrangements of biomolecules, especially from practical point of view. Effect of probe placement due to steric hindrance and random nature of biomolecules, are also considered. The capacitances associated with the nanogaps occupied by biomolecules, following various arrangements, are modeled. Expressions of the threshold voltage, drain current and its sensitivity in terms of variations are also derived using the capacitance model. A comparative study of the proposed and the existing architectures is made. The influence of process variation on the sensitivity of the sensor is also studied. The results from the proposed analytical model are validated with the simulated data obtained from TCAD device simulator. In conclusion, the proposed DM-DGFET based biosensor architecture will emerge as an optimal model, very useful for the study on this field in future.

Mixed-Dimensional 1D/2D van der Waals Heterojunction Diodes and Transistors in the Atomic Limit.

Inverting a semiconducting channel is the basis of all field-effect transistors. In silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs), a gate dielectric mediates this inversion. Access to inversion layers may be granted by interfacing ultrathin low-dimensional semiconductors in heterojunctions to advance device downscaling. Here we demonstrate that monolayer molybdenum disulfide (MoS2) can directly invert a single-walled semiconducting carbon nanotube (SWCNT) transistor channel without the need for a gate dielectric. We fabricate and study this atomically thin one-dimensional/two-dimensional (1D/2D) van der Waals heterojunction and employ it as the gate of a 1D heterojunction field-effect transistor (1D-HFET) channel. Gate control is based on modulating the conductance through the channel by forming a lateral p-n junction within the CNT itself. In addition, we observe a region of operation exhibiting a negative static resistance after significant gate tunneling current passes through the junction. Technology computer-aided design (TCAD) simulations confirm the role of minority carrier drift-diffusion in enabling this behavior. The resulting van der Waals transistor architecture thus has the dual characteristics of both field-effect and tunneling transistors, and it advances the downscaling of heterostructures beyond the limits of dangling bonds and epitaxial constraints faced by III-V semiconductors.

CuO Nanoparticles Decorated ZnO Nanorods Based Extended-Gate Field-Effect-Transistor (EGFET) for Enzyme-Free Glucose Sensing Application.

In this work, CuO nanoparticles (NPs) decorated zinc oxide nanorods (ZnO NRs) on fluorine-doped tin oxide (FTO) substrate has been used as a working electrode. This working electrode has been used as an extended gate for field-effect transistor. The main objective is to use the EGFET (extended gate field effect transistor) as a glucose sensor. The proposed glucose sensor has good sensitivity of 6.643 mV/mM with a wide range of linearity (1mM-8mM) which covers the glucose level of human blood ranging from 4.4 mM to 6.6 mM. This novel concept of the glucose sensing using CuO NPs decorated ZnO nanorods based EGFET may be explored for sensing other saccharides such as mannose, fructose, and sucrose. This vertically grown ZnO nanorods decorated with CuO NPs based electrode gives reliable selectivity, good repeatability, and more stability. The performance of proposed sensor is also compared with commercially available glucose sensors. The sensitivity performance of the glucose sensor also confirms the capability to detect the glucose level from human blood and serum.

Enzyme Free Detection of Glucose Using MgO Nanocubes Based Extended Gate N-channel MOSFET

MgO nanocubes were used as a sensing electrode material for detection of glucose in the extended gate field effect transistor (EGFET) configuration. MgO nanocubes were prepared by thermal CVD approach. Morphology and elemental composition of as-prepared MgO nanocubes were obtained using the scanning electron microscope (SEM) along with EDS. The sensing electrode was prepared by coating MgO nanocubes over the copper foil by doctor blade method and it was tested with various concentrations of glucose in Phosphate Buffer Saline (PBS) buffer solution. The MgO nanocubes coated electrode showed linear response for glucose concentrations from 1.6 mM to 25.6 mM. The sensitivity was calculated as 0.12 |aA/mM.cm2.

A ZIF-67 derived Co3O4 dodecahedron shaped microparticle electrode based extended gate field-effect transistor for non-enzymatic glucose detection towards the diagnosis of diabetes mellitus

The present study focuses on non-enzymatic glucose detection using an extended gate field-effect transistor (EGFET) based on zeolitic imidazole framework-67 (ZIF-67) derived cobalt tetraoxide (Co3O4) dodecahedron shaped microparticles.

Моделирование характеристик низковольтных вентилей на совмещённых цилиндрических полевых нанотранзисторах с полностью охватывающим затвором

The applicability of the architecture of a nanoscale surrounding gate field-effect transistor with a combined cylindrical working area for low-voltage applications is discussed. At the same time, the licensed TCAD Sentaurus instrument and technological modeling system is used as a tool. The transistor architecture under consideration involves combining the working zones of n-channel and p-channel transistors with one common gate. At the same time, the efficiency of suppressing short-channel effects is maintained and a high level of transistor current is provided in the strong inversion mode. Based on this architecture, a TCAD model of the NAND gate has been developed, the design of which contains two independent surrounding gates one combined working area. The use of the proposed gate architecture makes it possible to reduce the number of required transistor structures per gate by three times. This leads to a decrease in the switched capacity and power dissipation. From the simulation results, the gate geometric parameters with a working area length of 25 nm and a diameter of 8.5 nm, which can function at control voltages of 0.5 V in the frequency range up to 20 GHz with high gain, are determined. The switching time delay is 0.81 ps. The TCAD model of a half-adder is developed in the basis 2NAND. According to the simulation results, the efficiency of the prototype, which performs binary code addition operations with a delay of 4.2 ps at a supply voltage of 0.5 V and a frequency of 20 GHz, is shown. The obtained results create a theoretical basis for the synthesis of low-voltage complex functional blocks with high performance and minimal occupied area, which meets modern requirements for digital applications.

Screen-printed Ga2O3 thin film derived from liquid metal employed in highly sensitive pH and non-enzymatic glucose recognition

A new scaffold was introduced prefacing a screen-printed native gallium oxide (Ga2O3) layer derived from galinstan and pure metallic gallium, employed in Extended Gate Field Effect Transistor (EGFET) along with electrochemical measurement for pH and non-enzymatic glucose detection. Screen-printed Ga2O3 from galinstan exhibited a better pH sensitivity (79. 46 mV/pH) with 99% linearity and improved reliability compared to Ga2O3 derived from pure gallium. The highly selective Ga2O3 (from galistan) based glucose sensor exhibited high sensitivity (22.01 mV/mM) in EGFET and a minimum limit of detection (20 μM) in electrochemical measurement. The commercial applicability of the galinstan-based EGFET glucose sensor was examined by detecting glucose in human serum. Material characterization supported the electrical results. This approach is an innovative state-of-the-art for a stable, inexpensive, and reliable pH and glucose detection method at room temperature.

Modeling the Double Layer Capacitance Effect in Electrolyte Gated FETs with Gel and Aqueous Electrolytes.

Potential implementation of bio-gel Electrolyte Double Layer capacitors (bio-gel EDLCs) and electrolyte-gated FET biosensors, two commonly reported configurations of bio-electrolytic electronic devices, requires a robust analysis of their complex internal capacitive behavior. Presently there is neither enough of the parameter extraction literature, nor an effective simulation model to represent the transient behavior of these systems. Our work aims to supplement present transient thin film transistor modelling techniques with the reported parameter extraction method, to accurately model both bio-gel EDLC and the aqueous electrolyte gated FET devices. Our parameter extraction method was tested with capacitors analogous to polymer-electrolyte gated FETs, electrolyte gated Field effect transistor (EGOFET) and Organic Electrolyte Gated Field Effect Transistor (OEGFET) capacitance stacks. Our method predicts the input/output electrical behavior of bio-gel EDLC and EGOFET devices far more accurately than conventional DLC techniques, with less than 5% error. It is also more effective in capturing the characteristic aqueous electrolyte charging behavior and maximum charging capability which are unique to these systems, than the conventional DLC Zubieta and the Two branch models. We believe this significant improvement in device simulation is a pivotal step towards further integration and commercial implementation of organic bio-electrolyte devices. The effective reproduction of the transient response of the OEGFET equivalent system also predicts the transient capacitive effects observed in our previously reported label-free OEGFET biosensor devices. This is the first parameter extraction method specifically designed for electrical parameter-based modelling of organic bio-electrolytic capacitor devices.

PH sensor based on AuNPs/ ITO membrane as extended gate field-effect transistor

In the present work, gold nanoparticles/indium tin oxide (AuNPs/ITO) thin films were analyzed for pH sensing application based on extended gate field-effect transistor (EGFET). The AuNPs were synthesized through pulsed laser ablation in liquid (PLAL) technique. Afterwards, the AuNPs were deposited onto ITO thin film by electrospinning method. The AuNPs were characterized using transmission electron microscope (TEM) and UV–Vis spectroscope techniques. From the TEM analysis, the size of the spherical-shaped AuNPs was found to be in the range of 5–22 nm. The UV–Vis spectroscopy analysis revealed absorption peak at 518 nm, indicating purplish red color. The AuNPs/ITO thin films were also characterized using field emission scanning electron microscope (FE-SEM) and X-Ray Photoelectron Spectroscopy (XPS) technique. The depth of the films was 6.498 µm and the Au 4f doublet binding energy peaks of the photoelectrons at 83.79 and 87.45 eV. The current–voltage (I-V) curves indicated pH sensitivities values of 43.6 mV/pH and 0.6 μA1/2pH−1 with linear regression of 0.99 and 0.99 for pH voltage and current sensitivities, respectively. The hysteresis and drift characteristics of the prepared films were also done to investigate the stability and reliability of the films. The results of this work demonstrated that the AuNPs/ITO thin film is quite useful for the acidity and basicity detection.

Detection of pH and Urea with an Extended Gate Field-Effect Transistor Based Microsensor

Here, extended gate field-effect transistor-based (EGFET) microsensors have been developed for high sensitive detection of pH and urea. EGFET was made by integrating with a microelectrode. Briefly, the EGFET-based pH microsensor was developed by modifying the surface of a microelectrode with polypyrrole (PPy) via electropolymerization and integrating it with a small, simple and inexpensive metal oxide semiconductor field-effect transistor (MOSFET). As for the EGFET-based urea microsensor, urease enzyme was immobilized in PPy. The measurements of pH and urea were made in solutions at different pH values and urea concentrations, respectively. The results showed that the pH microsensor had a very good sensitivity of 67 mV/pH in a pH range of 5-12. Similarly, the EGFET-based urea microsensor showed a linear response range of 10-9 to 10-5 M urea with sensitivities of 35.5 mV/decade urea and 10 µA/decade urea. The reported EGFET-based pH and urea microsensors have great potential for use in the biomedical field, especially in applications where local analysis is required.

CeO2 nanoparticles based extended gate field effect transistor for enzyme free detection of glucose

CeO2 nanoparticles based extended gate field effect transistor for enzyme free detection of glucose

Investigation of X-ray Radiation Detectability Using Fabricated ZnO-PB Based Extended Gate Field-Effect Transistor as X-ray Dosimeters

A new design of the MOSFET dosimeter is being developed in a different study to measure the dose delivered to the tissue layers. Development of zinc oxide-Lead (ZnO-Pb) of different thicknesses fabricated by chemical bath deposition were investigated to study their sensitivity following irradiation using a low absorbed dose that can be used in diagnostic and interventional radiology (9, 36.5, and 70 mGy) and high absorbed dose (1, 5, and 10 Gy) of X-ray. The morphology and structure of the as-prepared films were analysed using FESEM and XRD measurements. The device relies on sensing the changes in the local electric field arising from radiation interactions in the absorber, coupled with the semiconductor materials used in this work—ZnO-Pb as the EGFET. Then the sensitivity of all devices was examined. Generally, thin-film devices showed less sensitivity to X-ray than the disk type. The sensitivity of the thin film dropped from 6.66 mV/to 1.42 mV/Gy, while the sensitivity of the ZnO-Pb disk type was 23.3 mV/Gy, which then dropped to 6.30 6.42 mV/Gy. Furthermore, the disk type ZnO-Pb was exposed to a high absorbed dose and obtained a sensitivity value of 0.08 mV/Gy, while the ZnO-Pb thin film obtained 0.01 mV/Gy. This can be related to the influence of thickness on the sensitivity of the dosimeter. However, the device’s performance characteristics, like sensitivity to radiation exposure and operating dose area, were discovered to be strongly dependent on the materials employed, effective atomic number, and thickness of the materials. Based on the results shown above, these devices might be considered a low-cost candidate for real-time -radiation dosimetry at room temperature. Furthermore, the thickest sample of 1 mm showed better sensitivity to radiation, compared to the thinner samples.