Field-effect Transistor Architecture Research Articles

Adapting single-walled carbon nanotube-based thin-film transistors to flexible substrates with electrolyte-gated configurations using a versatile tri-layer polymer dielectric.

Flexibility has been a key selling point in the development of carbon-based electronics and sensors with the promise of further development into wearable devices. Semiconducting single-walled carbon nanotubes (SWNTs) lend themselves well to applications requiring flexibility while achieving high-performance. Our previous work has demonstrated a tri-layer polymer dielectric composed of poly(lactic acid) (PLA), poly(vinyl alcohol) with cellulose nanocrystals (PVAc), and toluene diisocyanate-terminated poly(caprolactone) (TPCL), yielding an environmentally benign and solution-processable n-type thin-film transistor (TFT). Despite the potential for fabrication on flexible substrates, these devices were only characterized on rigid substrates. We present herein the fabrication of these TFTs on Kapton® substrates and a progression of the devices' n- and p-type operation over 7 days, demonstrating continuous loss of the n-type performance and relative stability of the p-type performance after 3 days in ambient air. The tri-layer dielectric is then applied in an electrolyte-gated SWNT field-effect transistor (EG-SWNT-FET) architecture, shielding the SWNTs from the electrolyte and allowing for width-normalised g m values of 0.0563 ± 0.0263 μS μm-1 and I ON/OFF ratios of 103-104 using de-ionized (DI) water as the electrolyte. Finally, as a proof of concept, the device was used to detect α-synuclein, a neuronal protein whose aggregation is associated with Parkinson's disease, in DI water through the immobilization of target specific aptamer molecules on the polymer layer covering the gate electrode.

Optically and electrically modulated artificial synapses based on MoS2/PZT ferroelectric field-effect transistor for neuromorphic computing system

To present an advanced device scheme of high-performance optoelectronic synapses, herein, we demonstrated the electrically- and/or optically-drivable multifaceted synaptic capabilities on the 2D semiconductor channel-based ferroelectric field-effect transistor (FeFET) architecture. The device was fabricated in the form of the MoS2/PZT FeFET, and its synaptic weights were effectively controlled by dual stimuli (i.e., both electrical and optical pulses simultaneously) as well as single stimuli (i.e., either electrical or optical pulses alone). This could be attributed to the electrical pulse-tunable strong ferroelectric polarization in PbZrxTi1−xO3 (PZT) as well as the polarization field-enhanced persistent photoconductivity effect in MoS2. Additionally, it was confirmed that the proposed device possesses substantial activity, achieving approximately 95 % pattern recognition accuracy. The results substantiate the great potential of the 2D semiconductor channel-based FeFET device as a high-performance optoelectronic synaptic platform, marking a pivotal stride towards the realization of advanced neuromorphic computing systems.

Enhancing Si1-XGex/Si Etch Rate Selectivity Using Etching Inhibitor in Radical Oxidation By Halide-Based Oxidant

As the technology node shrinks, innovation in the metal-oxide-semiconductor field-effect transistor (MOSFET) architecture has been required to mitigate the short-channel effects (SCE). Thus, planar FET had changed to FinFET and now gate-all-around FET (GAAFET) has been introduced with entering the 3-nm-generation. To fabricate GAAFET, selective etching of Si1-xGex- to Si-film is a key technology. According to the International Roadmap for Devices and Systems (IRDS™), the gate width of GAAFET is around 30 nm. Therefore, higher than 30 nm/min of etch rate for throughput and more than 400:1 of selectivity for acquiring a uniform Si-channel layer are required.As is well known, the etch rate in wet etching strongly depends on the standard reduction potential (SRP) of the oxidant. Our research group previously revealed the radical oxidation mechanism of sodium periodate (NaIO4) oxidant. In an acidic medium, NaIO4 can exist in periodate ion (IO4 -) form capable of generating hydroxyl radical (•OH). The high SRP value of hydroxyl radical (2.80 eV) compared to conventional oxidant, hydrogen peroxide (H2O2, 1.76 eV) and peracetic acid (PAA, 1.75 eV), resulted significantly high etch rate. In subsequent research, we introduced inhibitors reducing the Si-film etch rate to enhance Si1-xGex/Si etch rate selectivity when using sodium periodate as an oxidant.Acetic acid is commonly used as an additive in wet etchants to maintain uniform pH and control the etching of Si-film. However, it has several issues, strong vinegar odor, relatively large concentration to act, etc. Therefore, other additives are needed to substitute acetic acid. In selecting inhibitors, 2 factors are considered, i) scavenging effect for hydroxyl radical, and ii) hydrophobicity, as shown in Figure 1. Because the concentration of hydroxyl radical influences not only the Si1-xGex-film etch rate, but the Si-film etch rate, the scavenging effect of an inhibitor can reduce the film etch rate to enhance etch rate selectivity. Furthermore, the hydrophobicity part of inhibitors can build a hindrance layer on Si-film. Generally, Si-film has more hydrophobicity than Si1-xGex-film, inhibitors having hydrophobicity part are more prone to form a hindrance layer on Si-film than Si1-xGex-film. This results in the enhancement of Si1-xGex/Si etch rate selectivity by reducing Si-film considerably than Si1-xGex-film. The qualitative comparison of hydroxyl radical concentration depending on inhibitors and characterization methods to confirm the hindrance layer will be presented in detail. Acknowledgement This work was supported by the Technology Innovation Program (20022475, Development of wet Etchant capable of high selection etching in microprocesses below 10 nm) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) References [1] Lee, Seung-Jae, et al. "Extremely high selective Si1−xGex-film wet etchant generating highly dissolved oxygen via peracetic acid oxidant for lateral gate-all-around FETs with a logic node of less than 3-nm." Chemical Engineering Journal 475 (2023): 146257. Figure 1

Research on channel-exposed carbon-based FET humidity sensor

Abstract The ability to detect humidity is crucial for a variety of sectors, including industrial manufacturing, meteorological surveillance, and the preservation of materials, among others. Field effect transistor (FET) based sensor, renowned for its signal amplification effect, plays a pivotal role in detecting trace-level analytes with high sensitivity. Our work demonstrates the preparation of a humidity sensor based on carbon-based FET architecture, employing micro-nano processing techniques. In this work, semiconducting carbon nanotubes serve as the sensing material and channel at the same time. The outcomes indicate that the sensor exhibits a linear response ranging from 0% to 80% relative humidity (RH) and good repeatability. It also shows long-term stability in a 40-day test, proving potential applications in FET-type humidity sensors.

Tunneling field-effect transistors with two-dimensional BiN as the channel semiconductor

The lack of suitable channel semiconductor materials has been a limiting factor in the development of tunneling field-effect transistor (TFET) architectures due to the stringent criteria of both air stability and excellent gate-tunable electronic properties. Here, we report the performance limits of sub-10-nm double-gated monolayer (ML) BiN TFETs by utilizing first-principles quantum-transport simulations. We find that ML BiN possesses an indirect bandgap of 0.8 eV and effective masses of 0.24m0 and 2.24m0 for electrons and holes, respectively. The n-type BiN TFETs exhibit better performance than the p-type ones, and the on-state current can well satisfy the requirements of the International Roadmap for Devices and Systems for both high-performance and low-power standards. Notably, we find that the BiN TFETs exhibit distinguished gate controllability with an ultra-low subthreshold swing below 60 mV/decade even with a small gate length of 6 nm, which is superior to the existing field-effect transistors, such as black phosphorus TFETs, GeSe TFETs, and BiN metal–oxide–semiconductor field-effect transistors. Furthermore, the BiN TFETs are endowed with the potential to realize high switching speed and low-power consumption applications because of their extremely short delay time and ultra-low power-delay product. Our results reveal that the ML BiN is a highly competitive channel material for the next-generation TFETs.

Analysis fin field-effect transistor design with high-k insulators

In this article, we integrate a Fin Field Effect Transistor with high-k insulators to investigate the optimal design for chemical field effect transistors in order to give higher inductance (resulting in a higher transmission relationship), improved amplitude, and outcome-based substance. pH sensing was utilised to test the design. We investigated the responsiveness and linearity of silicon dioxide, oxide, and hafnium oxide as pH-sensing electromagnetic materials, as well as their chemical resistance in various acids. The device’s huge component ratio and fin shape allow for high currents and a more dependable planar conducting channel than conventional silicon nanowires. The hafnium oxide Fin Field Effect Transistor architecture delivered the greatest results, with the most linear features of generation and turnover and a broader dynamic range. The chemical stability of hafnium oxide was also the best. As a result, we believe the large component ratio Fin Field Effect Transistors/high-k dielectric combination can provide the optimal process fairness for Field-Effect Transistor-based sensors. The authors propose a novel seamless embedded induction approximation with a quaternary resonator. Only one deleterious modified divergent voltage current conveyor, one of the suggested quaternary synthesisers, uses a Z input, a rectifier, and two crossed capacitive. In the intended unidirectional isolated circuit emulator, just one customised split electrical output feeder with a sole Z electrode, two switches, and the first neutral capacitor are used. The suggested seamless rooted circuit simulation just requires a specific passive constituent compatibility criterion. In addition, the suggested lossless grounded inductor simulator yields a ring filter application. To illustrate the performance of all the circuits, a variety of models using the LTSPICE software, the cadence virtuoso 7nm parameter, and data analyses were performed.

Selective Detection of Functionalized Carbon Particles based on Polymer Semiconducting and Conducting Devices as Potential Particulate Matter Sensors.

This paper reports a new mechanism for particulate matter detection and identification. Three types of carbon particles are synthesized with different functional groups to mimic the real particulates in atmospheric aerosol. After exposing polymer-based organic devices in organic field effect transistor (OFET) architectures to the particle mist, the sensitivity and selectivity of the detection of different types of particles are shown by the current changes extracted from the transfer curves. The results indicate that the sensitivity of the devices is related to the structure and functional groups of the organic semiconducting layers, as well as the morphology. The predominant response is simulated by a model that yielded values of charge carrier density increase and charge carriers delivered per unit mass of particles. The research points out that polymer semiconductor devices have the ability to selectively detect particles with multiple functional groups, which reveals a future direction for selective detection of particulate matter.

Effects of Thermal Boundary Resistance on Thermal Management of Gallium-Nitride-Based Semiconductor Devices: A Review.

Wide-bandgap gallium nitride (GaN)-based semiconductors offer significant advantages over traditional Si-based semiconductors in terms of high-power and high-frequency operations. As it has superior properties, such as high operating temperatures, high-frequency operation, high breakdown electric field, and enhanced radiation resistance, GaN is applied in various fields, such as power electronic devices, renewable energy systems, light-emitting diodes, and radio frequency (RF) electronic devices. For example, GaN-based high-electron-mobility transistors (HEMTs) are used widely in various applications, such as 5G cellular networks, satellite communication, and radar systems. When a current flows through the transistor channels during operation, the self-heating effect (SHE) deriving from joule heat generation causes a significant increase in the temperature. Increases in the channel temperature reduce the carrier mobility and cause a shift in the threshold voltage, resulting in significant performance degradation. Moreover, temperature increases cause substantial lifetime reductions. Accordingly, GaN-based HEMTs are operated at a low power, although they have demonstrated high RF output power potential. The SHE is expected to be even more important in future advanced technology designs, such as gate-all-around field-effect transistor (GAAFET) and three-dimensional (3D) IC architectures. Materials with high thermal conductivities, such as silicon carbide (SiC) and diamond, are good candidates as substrates for heat dissipation in GaN-based semiconductors. However, the thermal boundary resistance (TBR) of the GaN/substrate interface is a bottleneck for heat dissipation. This bottleneck should be reduced optimally to enable full employment of the high thermal conductivity of the substrates. Here, we comprehensively review the experimental and simulation studies that report TBRs in GaN-on-SiC and GaN-on-diamond devices. The effects of the growth methods, growth conditions, integration methods, and interlayer structures on the TBR are summarized. This study provides guidelines for decreasing the TBR for thermal management in the design and implementation of GaN-based semiconductor devices.

Side charge propagation in simultaneous KPFM and transport measurement of humidity exposed graphene FET sensor

The surface diffusion (dissipation) of charge carriers enhanced by water molecules in solution-based biosensors and ambient operating gas sensors strongly influence their resistance response, sensitivity, and stability in time. Therefore, the information on the charge distribution at interfaces of conductive and insulating parts is essential for the operating sensors. This work presents the simultaneous measurement of the longitudinal macroscopic resistance response and local surface potential (SP) mapping by Kelvin probe force microscopy (KPFM) on a graphene Hall bar sensor. The results show the propagation of an electric charge from the main graphene channel onto the neighboring SiO2 surface. The charge propagation strongly increases with the relative humidity and can be controlled by a bottom-gate voltage used in most sensors based on a field effect transistor (FET) architecture. As proved by the longitudinal resistance measurements, the resulting side charge accumulation has a very small impact on the 2D resistivity of the graphene channel. It has been explained by an application of the Thomas-Fermi theory, proving an efficient screening of side accumulated charge potential caused by a redistribution of the charge inside the wide graphene channel. The combination of a transport resistance response and KPFM provides a deeper understanding of sensors/biosensors functionality and their design features than a simple resistance response usually observed.

Suppression of P-I-N forward leakage current in tunnel field-effect transistor

In this paper, we propose a tunnel field-effect transistor (TFET) architecture for the suppression of P-I-N forward leakage current. The P-I-N forward leakage current is attributed to the drift-diffusion mechanism under the forward-bias condition; thereby, the gate loses all of its control over the channel. In the proposed device architecture, the source region is bifurcated into sub-regions (referred to as P+ and P++) with different p-type doping concentrations. We introduce an electrostatic source (ES) electrode over the oxide, which encapsulates the lowly doped (P+) source region. The ES is shorted to the source electrode, implying that a positive voltage at the source terminal causes the ES to turn positive, resulting in a decrement in the P+ characteristics in the source region. On the other hand, the increment in voltage causes the P+ source region to become an intrinsic region, thus minimizing the chances of the P-I-N diode becoming forward biased. In the proposed device architecture, by tuning the work function values of the ES, the P-I-N forward leakage current is suppressed by 3–6 orders of magnitude at the cost of the ON-state current loss of 3–10-fold of magnitude. Considering the detrimental impact of P-I-N forward leakage current in circuits, this small penalty on the part of the ON-state current is worth accepting for the significant reduction in parasitic P-I-N forward leakage current. We believe that the proposed technique will pave the way for widespread use of TFETs in logic circuits.

Unlocking the Potential of Field Effect Transistor (FET) Biosensors: A Perspective on Methodological Advances in Computational and Molecular Biology

AbstractField‐effect transistor (FET)‐based sensors are increasingly gaining relevance in diagnostic, healthcare, and environmental monitoring applications. A FET operates by transducing chemical interactions between a surface‐immobilized bioreceptor and the target analyte into a detectable electrical signal. FET biosensors can detect and monitor molecules (i.e., biomarkers, small molecules, viruses, bacterias) present in liquid samples, making a “liquid gate” configuration of FETs the most suitable approach. However, this FET architecture presents dimensional constraints that affect bioreceptors’ stability and immobilization in the liquid phase. To overcome these limitations, herein, a combination of computational and molecular biology techniques for improving bioreceptors' applicability in biosensing is proposed. This results in the optimized and problem‐tailored protein receptors for specific FET biosensors applications, thus enhancing their overall performance. The interplay between the computational and experimental approaches will represent a ground‐breaking solution for the development of next‐generation biosensors.

Pushing On-Chip Photosensitivity Forward Using Edge-Driven Vertical Organic Phototransistors

Developing high-performance photosensors using prototype device architectures is essential to pushing forward developing and advancing next-generation optoelectronic applications. This work reports an organic phototransistor (OPT) with an ultra-short conducting channel (tens of nanometers) and outstanding photoelectric conversion efficiency. The OPT is based on a vertical organic field-effect transistor (VOFET) architecture, which utilizes a rolled-up metallic nanomembrane (NM) as the drain electrode and a photolithographically patterned (rectangular-shaped) perforated source electrode. These features expand the concept of conventional VOFETs as the former enables the incorporation of ultra-thin active layers and allows reliable control over gate-induced modulation of channel current. Using the engineering as abovementioned strategies, we focused on obtaining an improved device performance, studying their fundamental operating principle, and further investigating their application as photosensors. The optimized devices exhibited low operating voltages (<5 V) and enhanced on/off current ratio (∼105). The VOFET photoresponse was characterized by measuring the electrical characteristics in the dark and under illumination using three different monochromatic light colors. Under blue light, our devices demonstrated impressive photosensitivity (Pmax ≈ 105) and fast photoelectric conversion (steep light-induced threshold voltage shift), demonstrating that the rolled-up NM OPT shows excellent potential as a highly sensitive photodetector with low power consumption.

Comprehensive study of gate induced drain leakage in nanowire and nanotube junctionless FETs using Si1-xGex source/drain

We present, in this paper, optimized nanotube (NT) and nanowire (NW) junctionless field-effect transistor (JLFET) architectures of gate-induced drain leakage (GIDL). At the source/ drain–channel interface, SiGe creates a valence energy band discontinuity which alleviates lateral band-to-band tunneling (L-BTBT) of electrons in the OFF-state. It is established through 2-D TCAD simulations that inclusion of SiGe decreases L-BTBT in the NTJLFET by >5 orders, thus leading to a substantial ION/IOFF of with precision 1012 for a 20 nm gate length which is not attainable in the conventional NTJLFET (ION/IOFF ∼ 106). Furthermore, degraded OFF-state current in NWJLFET because of conventional charge-sharing effect improves with the inclusion of SiGe by ∼2 orders of magnitude. Additionally, it is effective to place SiGe layers positioned at the source and drain regions and SiGe/ Si interface inside or at the channel region. Based on the proposed design guidelines, we show that the optimized SiGe S/D NTJLFET is effective in reduction of L-BTBT GIDL when gate length is scaled to 5 nm.

Supported Pt Nanoclusters on Single-Layer MoS2 for the Detection of Cortisol: From Atomistic Scale to Device Modeling

The development of nonenzymatic sensors is a challenge which requires, on the one hand, careful design of the sensing materials with respect to the chosen analyte, and on the other hand, suitable device architectures. In this work, we propose single-layer molybdenum disulfide (MoS2) decorated with subnanometer Pt clusters as the sensing platform for the detection of cortisol. The aim is to assess the suitability of such a sensing platform for the development of wearable and portable cortisol sensors. For this study, we performed multiscale computer simulations at the materials level up to device scale. First, ab initio simulations within the framework of density functional theory (DFT) allowed us to gain insights into the interaction, at the atomic level, between the analyte (cortisol) and the sensing platform (MoS2/Pt). Then, by carrying out technology computer-aided design (TCAD) simulations, we were able to consider a device architecture and investigate its performance as cortisol sensor. Following our multiscale simulation strategy, we were able to assess the proposed field-effect transistor (FET) sensor, whose channel is made of Pt-decorated MoS2. The sensing mechanism relies on the chemiresistive response of the device to the adsorption of cortisol on the channel, which leads to a sizable charge transfer from the analyte to the substrate and, consequently, to the measurable shift in the gate voltage threshold of the FET. Our findings suggest that both the choice of the sensing materials and the proposed FET architecture are suitable for detecting cortisol by non-enzymatic means. In the best case scenario, we predict theoretical gate voltage shifts between 76 and 780 mV with respect to the cluster concentration and between 27 and 780 mV when varying the cluster occupancy by cortisol. We may expect our results to provide the necessary basis to develop highly sensitive nonenzymatic cortisol sensors based on 2D materials decorated with Pt nanoclusters.

Investigation of the dielectrically modulated electron hole bilayer tunnel field effect transistor for biomolecule detections

This work investigates a Dielectrically Modulated Electron-Hole Bilayer Tunnel Field Effect Transistor (DM-EHBTFET) architecture for biosensing applications using extensive numerical device simulation. The proposed DM-EHBTFET structure incorporates extended source and drain pockets in the channel to ensure vertical band-to-band tunneling (BTBT) dominated transduction. The underlying device physics and sensing performance of the proposed DM-EHBTFET has been comprehensively analyzed based on the tunneling length sensitivity and drain current sensitivity, respectively. Finally, an extensive comparative performance study has been undertaken against conventional lateral tunneling (LT) and vertical tunneling (VT) based DMTFETs, as well as reported state-of-art DMTFETs and DMFETs. The results demonstrate that the optimized DM-EHBTFET outperforms both conventional LT-/VT- DMTFETs with more than 500 times and 150 times improvements in sensitivity, respectively, over a range of biomolecule specifications, and more than 100 times sensitivity improvement has been observed in DM-EHBTFET over reported DMFETs/DMTFETs for lower biomolecule dielectric constant.

Performance Analysis of the Dielectrically Modulated Junction-Less Nanotube Field Effect Transistor for Biomolecule Detection.

The design of a high-performance Dielectrically Modulated Field Effect Transistor (DMFET) with smaller device dimension (channel length ≤ 100nm) has recently drawn significant research attention for point-of-care (POC) diagenesis applications. Driven by this paradigm, a Hetero-Gate Metal Dielectrically Modulated Junction-Less Nanotube Field Effect Transistor (DM-JLNFET) architecture is introduced and systematically investigated for label-free electrochemical biosensing application with the help of extensive numerical device simulations. The DM-JLNFET is carefully designed to exploit the advantages of superior gate control over channel electrostatics and electron injection component as well as strong immunity towards the short channel effects that lead to a notably high sensing performance compared to its conventional counterparts. In this context, the underlying physics of the transduction mechanism is analyzed in detail based on the device electrostatics and the carrier transport mechanism. The sensing performance of the proposed biosensor is quantified in terms of the drain current and threshold voltage sensitivities, which represents the relative modulations in these parameters with biomolecule conjugation. Typically, the DM-JLNFET exhibits a drain current and threshold voltage sensitivities as high as 1×10 12 and 0.70, respectively, for biomolecule dielectric constant above 2. Furthermore, the sensing performance demonstrates strong immunities towards non-uniform cavity occupancy. Finally, extensive comparative performance analysis with Dielectrically Modulated Nanowire Field Effect Transistor (DM-NWFET) is performed. The results exhibit that the proposed DM-JLNFET can offer more than 100% and eight orders of magnitude improvements in the threshold voltage and drain current sensitivities, respectively, for a range of small biomolecule dielectric constants.

Dual-gated single-molecule field-effect transistors beyond Moore\u2019s law

As conventional silicon-based transistors are fast approaching the physical limit, it is essential to seek alternative candidates, which should be compatible with or even replace microelectronics in the future. Here, we report a robust solid-state single-molecule field-effect transistor architecture using graphene source/drain electrodes and a metal back-gate electrode. The transistor is constructed by a single dinuclear ruthenium-diarylethene (Ru-DAE) complex, acting as the conducting channel, connecting covalently with nanogapped graphene electrodes, providing field-effect behaviors with a maximum on/off ratio exceeding three orders of magnitude. Use of ultrathin high-k metal oxides as the dielectric layers is key in successfully achieving such a high performance. Additionally, Ru-DAE preserves its intrinsic photoisomerisation property, which enables a reversible photoswitching function. Both experimental and theoretical results demonstrate these distinct dual-gated behaviors consistently at the single-molecule level, which helps to develop the different technology for creation of practical ultraminiaturised functional electrical circuits beyond Moore’s law.

Ultrasensitive and Selective Bacteria Sensors Based on Functionalized Graphene Transistors

We propose here a graphene biosensor based on the field-effect transistor (FET) architecture for continuous and real-time monitoring of bacteria, with beneficial features including facile operation, low-cost, selectivity, and high sensitivity. Our sensing device consists of the chemical-vapor-deposition (CVD) graphene monolayer, functionalized by the phage tail spike proteins (TSPs) that form specific binding sites to capture E. coli bacteria. We have investigated effects of surface functionalization and bacteria binding on the conductance of atomically thin graphene that determines transfer characteristics of a graphene FET (GFET). We have experimentally demonstrated that the concentration of E. coli bacteria can be selectively and accurately detected (at the single bacterium level) by a TSP-functionalized GFET. The proposed graphene biosensor may be of great interest for rapid, efficient detection of bacterial pathogens that could potentially pose a severe threat to human, animal, or plant health.

Unexpected Electron Transport Suppression in a Heterostructured Graphene-MoS2 Multiple Field-Effect Transistor Architecture.

We demonstrate a graphene–MoS2 architecture integrating multiple field-effect transistors (FETs), and we independently probe and correlate the conducting properties of van der Waals coupled graphene–MoS2 contacts with those of the MoS2 channels. Devices are fabricated starting from high-quality single-crystal monolayers grown by chemical vapor deposition. The heterojunction was investigated by scanning Raman and photoluminescence spectroscopies. Moreover, transconductance curves of MoS2 are compared with the current–voltage characteristics of graphene contact stripes, revealing a significant suppression of transport on the n-side of the transconductance curve. On the basis of ab initio modeling, the effect is understood in terms of trapping by sulfur vacancies, which counterintuitively depends on the field effect, even though the graphene contact layer is positioned between the backgate and the MoS2 channel.

Performance Analysis of the Diagonal Tunneling-Based Dielectrically Modulated Tunnel FET for Bio-Sensing Applications

In this work, a Diagonal Tunneling Dielectrically Modulated Tunnel Field Effect Transistor (DT-DMTFET) architecture is proposed for label-free bio-sensing application. The performance of this sensor architecture is comprehensively investigated with the help of extensive numerical device simulations. The architecture has been carefully engineered to exploits the diagonal band to band tunneling (BTBT) component in favor of bio-molecule detection. The essential physics of the transduction mechanism for lateral tunneling, vertical tunneling, and diagonal tunneling-based DMTFETs is extensively analyzed from device electrostatics and transport mechanisms. The transduction efficiency of the sensor devices is quantitatively assessed in terms of current sensitivity, where DT-DMTFET exhibits a sensitivity of 3590 compared to 2514 and 1550 observed in lateral tunneling (LT) and vertical tunneling (VT) dominated DMTFETs, respectively. The optimum sensitivity of DT-DMTFET is observed at 4V and 0.4 V gate and drain biases ranges of operation, where the same is observed at a gate bias of 5V and 7V for LT- and VT- DMTFET, respectively. Furthermore, the device design aspects are studied in detail to identify the relevant structural parameters and subsequently optimize the sensing performance of the DT-DMTFET. Finally, an extensive comparative performance study establishes that the DT-DMTFETs offer more than 50% and 100 % improvements in the current sensitivity compared to their lateral and vertical tunneling-based counterparts, respectively, over a range of bio-molecule sample specifications.