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Ferroelectric (FE) materials are key to advancing electronic devices owing to their non-volatile properties, rapid state-switching abilities, and low-energy consumption. FE-based devices are used in logic circuits, memory-storage devices, sensors, and in-memory computing. However, the primary challenge in advancing the practical applications of FE-based memory is its reliability. To address this problem, a novel polarization pruning (PP) method is proposed. The PP is designed to eliminate weakly polarized domains by applying an opposite-sign pulse immediately after a program or erase operation. Significant improvements in the reliability of ferroelectric devices are achieved by reducing the depolarization caused by weakly polarized domains and mitigating the fluctuations in the ferroelectric dipole. These enhancements include a 25% improvement in retention, a 50% reduction in read noise, a 45% decrease in threshold voltage variation, and a 72% improvement in linearity. The proposed PP method significantly improves the memory storage efficiency and performance of neuromorphic systems.

Due to their unique optical properties, colloidal nanocrystals (NCs) have transitioned from a solution processable luminescent liquid to an established building block for optoelectronics. As devices get more advanced, a higher degree of refinement is also required for the probe used to investigate their electronic structure. For long, device optimization has relied on the measurement of physical properties of the pristine material, assuming that they would be maintained after device integration. However, such an assumption neglects the realistic dielectric environment and possibly applied electric fields to drive the device. Hence, tools compatible with operando investigation of the electronic structure are required. Here, we review and present additional results relative to the operando investigation of infrared NCs using photoemission microscopy. This technique combines the advantages of photoemission to unveil band alignment with a sub-µm spatial resolution that is used to correlate energy shift to the device geometry. This method gives direct access to parameters such as diode built-in potential, transistor lever arm, or even the vectorial distribution of the electric field that are otherwise only attainable through indirect methods involving modelling. We provide indications and precautions to be used in the design of devices to permit the operando analysis via photoemission techniques. It is, therefore, a very promising tool for the optimization of NC-based devices. [ABSTRACT FROM AUTHOR]

Diamond is renowned as the ultimate semiconductor thanks to its exceptional physical properties, including unmatched hardness, exceptional wear resistance, superior mechanical and tribological characteristics, and high fracture strength. Diamond solution-gate field-effect transistors (D-SGFETs) leverage these advantages, along with their outstanding high-power and high-frequency performance, excellent thermal conductivity, wide bandgap, high carrier mobility, and rapid saturation speed. These features make D-SGFETs highly promising for fast and precise biomedical detection applications. This paper provides a comprehensive review of the fabrication techniques for diamond SGFETs, encompassing diamond film synthesis, surface conduction layer formation, source/drain fabrication, and FET packaging. Furthermore, the study delves into the surface functionalization of diamond SGFETs and their diverse applications in biomedical detection. Finally, the paper discusses the future outlook of diamond SGFETs in advancing biomedical detection technologies. [ABSTRACT FROM AUTHOR]

In low frequency band, miniaturized EMC(Electromagnetic Compatibility) test antennas are mostly electrically small antennas, which have the problems of high antenna factor and low test sensitivity. To solve the problem, based on active matching technology, the electrically small antennas loaded with negative impedance converter circuit and field effect transistor high-impedance input circuit are simulated and analyzed respectively. The simulation results show that the field effect transistor high-impedance input circuit has advantages over the negative impedance converter circuit in the ability of reducing antenna factor and the stability of circuit, and is helpful to the design and implementation of miniaturized EMC test antenna. The test results of the miniaturized EMC test antenna loaded with field effect transistor high-impedance input matching circuit show that, in 2~30 MHz, antenna factor can be improved by 22~46 dB compared with the EMC test antenna without matching circuit. [ABSTRACT FROM AUTHOR]

Adders and subtractors are essential to many integrated circuits (IC), including microprocessors, and micro controllers. However, using complementary metal oxide semiconductor (CMOS) and field effect transistor (FET) technology to make conventional adders and subtractors increased transistor count and power consumption. So, this effort begins with hybrid adder-subtractor designs using FinFET and graphene nano-ribbon FET(GnrFET) nano technologies. Initial development of an enhanced full adder with carry prediction (EFOCP) based on multiplexer logic with rapid carry-output selection reduced sum estimation delays. The considerable reduction in carry-output selection time led to this finding. The dynamic path auto-configurable adder (DPAA) selects high-speed and low-speed carry propagation channels using the EFOCP module. The DPAA was also used to create a two-complement based dynamic path auto-configurable subtractor (DPAS). Last, the dynamic path auto-configurable joint adder-subtractor (DPAJAS) combines DPAA and DPAS. Compared to existing approaches, the proposed DPAJAS design reduces Total Energy Consumption (TEC) by 23.3%, Total Path Delay (TPD) by 17.9%, and Carry Out Rise Delay by 18.2%. It also reduces Carry Out Fall Delay (COFD) by 19.4%, Sum Rise Delay (SRD) by 18.2%, and Sum Fall Delay by 18.3%. Finally, the proposed DPAJAS reduces Average Power Consumption (APC) 17.6%. These enhancements demonstrate the higher performance and efficiency of the proposed EFOCP, DPAA, DPAS, and DPAJAS designs. [ABSTRACT FROM AUTHOR]

The hybridization of MXene materials and transition metal dichalcogenides has a significant impact on heterojunction properties. The transport properties and electronic structure of heterojunctions of semiconducting MoS2 and metallic MXene Nb2C were studied by integrating density functional theory with non-equilibrium Green's function theory. The hybridization between Nb2C and MoS2 makes the tunneling barrier between the two layers disappear, which can enhance the electron injection efficiency from the Nb2C to the MoS2. Moreover, the Nb2C/MoS2 heterojunction exhibits a conventional n-type Schottky contact with a barrier height of 0.14 eV, which is significantly lower than the barrier height of 0.29 eV at the Ti/MoS2 junction. These factors result in a field-effect transistor with a low contact resistance of 138 Ω· μ m and a higher current of 1.09 mA μ m−1 at a bias voltage of 0.3 V applied between the left and right electrodes. Following the application of gate voltage, the I on/ I off ratio reaches 1266. [ABSTRACT FROM AUTHOR]

The family of 2D chalcogenide semiconductors has been growing rapidly. Metal monochalcogenides, for instance, can enable new possibilities in functional electronics and optoelectronics. A Gallium Selenide (GaSe) thin flake is used to fabricate a back gated field effect transistor (FET) with n‐type conduction behavior and wide hysteresis at the ambient conditions. The device shows high mobility up to 28 cm2 V−1 s−1 with Ion/Ioff ratio over 103. Under the laser exposure, the device shows a decrease in the threshold voltage and a left‐shift of the transfer characteristic with a slight increase in the current. The transfer characteristic exhibits a hysteretic behavior with hysteresis width linearly dependent on the applied gate voltage. Moreover, the GaSe‐based FET shows a photo response with a photoresponsivity of 475 mAW−1 and detectivity of 4.6 × 1012 Jones. The photocurrent rise and decay times are 0.1 and 1.3 s, respectively. Furthermore, the GaSe FET device can be used as a performant memory device with well separated states and memory window enhanced by the laser exposure, confirming an optoelectronic memory class. [ABSTRACT FROM AUTHOR]

Abstract Ferroelectric (FE) materials are key to advancing electronic devices owing to their non‐volatile properties, rapid state‐switching abilities, and low‐energy consumption. FE‐based devices are used in logic circuits, memory‐storage devices, sensors, and in‐memory computing. However, the primary challenge in advancing the practical applications of FE‐based memory is its reliability. To address this problem, a novel polarization pruning (PP) method is proposed. The PP is designed to eliminate weakly polarized domains by applying an opposite‐sign pulse immediately after a program or erase operation. Significant improvements in the reliability of ferroelectric devices are achieved by reducing the depolarization caused by weakly polarized domains and mitigating the fluctuations in the ferroelectric dipole. These enhancements include a 25% improvement in retention, a 50% reduction in read noise, a 45% decrease in threshold voltage variation, and a 72% improvement in linearity. The proposed PP method significantly improves the memory storage efficiency and performance of neuromorphic systems.

Two-dimensional transition metal dichalcogenide (TMDC) semiconductors are emerging as strong contenders for electronic devices that can be used in highly radioactive environments such as outer space where conventional silicon-based devices exhibit nonideal characteristics for such applications. To address the radiation-induced interface effects of TMDC-based electronic devices, we studied high-energy proton beam irradiation effects on the electrical properties of field-effect transistors (FETs) made with tungsten diselenide (WSe2) channels and hexagonal boron-nitride (hBN)/SiO2 gate dielectrics. The electrical characteristics of WSe2 FETs were measured before and after the irradiation at various proton beam doses of 1013, 1014, and 1015 cm−2. In particular, we demonstrated the dependence of proton irradiation-induced effects on hBN layer thickness in WSe2 FETs. We observed that the hBN layer reduces the WSe2/dielectric interface effect which would shift the transfer curve of the FET toward the positive direction of the gate voltage. Also, this interface effect was significantly suppressed when a thicker hBN layer was used. This phenomenon can be explained by the fact that the physical separation of the WSe2 channel and SiO2 dielectric by the hBN interlayer prevents the interface effects originating from the irradiation-induced positive trapped charges in SiO2 reaching the interface. This work will help improve our understanding of the interface effect of high-energy irradiation on TMDC-based nanoelectronic devices. [ABSTRACT FROM AUTHOR]

2D semiconductors have emerged as candidates for next‐generation electronics. However, previously reported 2D transistors which typically employ the gate‐first process to fabricate a back‐gate (BG) configuration while neglecting the thorough impact on the dielectric capping layer, are severely constrained in large‐scale manufacturing and compatibility with complementary metal–oxide–semiconductor (CMOS) technology. In this study, dual‐gate (DG) field‐effect transistors have been realized based on wafer‐scale monolayer MoS2 and the gate‐last processing, which avoids the transfer process and utilizes an optimized top‐gate (TG) dielectric stack, rendering it highly compatible with CMOS technology. Subsequently, the physical mechanism of TG dielectric deposition and the corresponding controllable threshold voltage (VTH) shift is investigated. Then the fabricated TG‐devices with a large on/off ratio up to 1.7 × 109, negligible hysteresis (≈14 mV), and favorable stability. Additionally, encapsulated TG structured photodetectors have been demonstrated which exhibit photo responsivity (R) up to 9.39 × 103 A W−1 and detectivity (D*) ≈2.13 × 1013 Jones. The result paves the way for future CMOS‐compatible integration of 2D semiconductors for complex multifunctional IC applications. [ABSTRACT FROM AUTHOR]

The fabrication of van der Waals heterostructures (vdWHs) has drawn considerable interest because of their wide range of functionalities. Herein, a novel PdSe2/ReSe2 vdWHs with gate‐tunable rectification behavior and excellent broadband photodetection characteristics is presented. The application of the gate bias substantially enhances the rectification behavior, with the highest rectification ratio (≈3.13 × 103) observed at gate voltage Vg = −60 V. The density functional theory calculations demonstrate the direct and indirect bandgap behavior of PdSe2 and ReSe2 in the monolayer structure, respectively. Additionally, the PdSe2/ReSe2 heterojunction displays a strong photo‐response in the near‐infrared region and achieves a high photoresponsivity, an excellent external quantum efficiency, and rapid rise and decay times of 1.7 × 103 A W−1, 4.05 × 103, and 5 and 20 ms, respectively. Furthermore, the device exhibits a remarkable detectivity of ≈3.5 × 1012 Jones. The findings hold great potential for advancing the fabrication of multifunctional vdW heterostructure devices. [ABSTRACT FROM AUTHOR]

Abstract Gas sensors based on micro‐electromechanical systems (MEMS) offer advantages such as a broad spectrum of potentially sensitive materials and analytes, easy miniaturization and integration, high sensitivity, and low costs. This paper introduces a novel MEMS sensor platform utilizing a suspended gate field effect transistor (SGFET) transducer. In this approach, the flexible gate membrane of the SGFET is coated with a sensitive material exhibiting responsive swelling behavior. For the proof of concept, kraft lignin hydrogel is chosen as a biorenewable material for humidity sensing. A precision dispensing technique is used to deposit kraft lignin hydrogel on the SGFETs. The sensor measurements yield reversible shifts in the sensor's output current of up to 9% in response to 5000 ppm water vapor. The results successfully demonstrate the feasibility of this new sensing platform.

Abstract The family of 2D chalcogenide semiconductors has been growing rapidly. Metal monochalcogenides, for instance, can enable new possibilities in functional electronics and optoelectronics. A Gallium Selenide (GaSe) thin flake is used to fabricate a back gated field effect transistor (FET) with n‐type conduction behavior and wide hysteresis at the ambient conditions. The device shows high mobility up to 28 cm2 V−1 s−1 with Ion/Ioff ratio over 103. Under the laser exposure, the device shows a decrease in the threshold voltage and a left‐shift of the transfer characteristic with a slight increase in the current. The transfer characteristic exhibits a hysteretic behavior with hysteresis width linearly dependent on the applied gate voltage. Moreover, the GaSe‐based FET shows a photo response with a photoresponsivity of 475 mAW−1 and detectivity of 4.6 × 1012 Jones. The photocurrent rise and decay times are 0.1 and 1.3 s, respectively. Furthermore, the GaSe FET device can be used as a performant memory device with well separated states and memory window enhanced by the laser exposure, confirming an optoelectronic memory class.

Photodetection is one of the vital functions for the multifunctional "More than Moore" (MtM) microchips urgently required by Internet of Things (IoT) and artificial intelligence (AI) applications. The further improvement of the performance of photodetectors faces various challenges, including materials, fabrication processes, and device structures. We demonstrate in this work MoS2 photodetectors with a nanoscale channel length and a back-gate device structure. With the mechanically exfoliated six-monolayer-thick MoS2, a Schottky contact between source/drain electrodes and MoS2, a high responsivity of 4.1 × 103 A W-1, and a detectivity of 1.34 × 1013 cm Hz1/2 W-1 at 650 nm were achieved. The devices are also sensitive to multiwavelength lights, including 520 and 405 nm. The electrical and optoelectronic properties of the MoS2 photodetectors were studied in depth, and the working mechanism of the devices was analyzed. The photoinduced Schottky barrier lowering (PIBL) was found to be important for the high performance of the phototransistor.

Two-dimensional (2D) materials play a crucial role as fundamental electrical components in modern electronics and optoelectronics next-generation artificial intelligent devices. This study presents a methodology for creating a laterally uniform p–n junction by using a partial oxygen plasma-mediated strategy to introduce p-type doping in single channel MoTe2 device. The MoTe2 field effect transistors (FETs) show high electron mobility of about ∼23.54 cm2 V−1 s−1 and a current ON/OFF ratio of ∼106 while p-type FETs show hole mobility of about ∼9.25 cm2 V−1 s−1 and current ON/OFF ratio ∼105 along with artificially created lateral MoTe2 p–n junction, exhibited a rectification ratio of ∼102 and ideality factor of ∼1.7 which is proximity to ideal-like diode. Thus, our study showed a diversity in the development of low-power nanoelectronics of next-generation integrated circuits.

This study introduces a novel three-dimensional (3D) vertical field-effect transistor (FET) structure that utilizes two-dimensional (2D) graphene as the channel, with channel length controlled by deposited dielectric thickness. The dielectric deposition process allows for the easier implementation of small-scale features on the order of nanometers compared to traditional patterning processes. Incorporating 3D vertical structures with 2D channel materials enhances device performance beyond conventional planar designs. The fabrication process involves direct graphene growth for the channel and nanometer-scale dielectric deposition for the facile adjustment of channel length. The experimental results validate successful graphene formation and transistor operation, as evidenced by current–voltage characteristics. The 3D Vertical FET holds promise for improved device integration and overall system performance due to its unique device structure and an effective short-channel implementation method. This research underscores the potential of 2D materials in advancing transistor technology, and presents a practical approach for increasing device density and enhancing performance in semiconductor production processes. [ABSTRACT FROM AUTHOR]

A proposal for a novel gate-all-around (GAA) polycrystalline silicon nanowire (poly-SiNW) field effect transistor (FET) is presented and discussed in this paper. The device architecture is based on the realization of poly-SiNW in a V-shaped cavity obtained by tetra methyl ammonium hydroxide (TMAH) etch of monocrystalline silicon (100). The device's behavior is simulated using Silvaco commercial software, including the density of states (DOS) model described by the double exponential distribution of acceptor trap density within the gap. The electric field, potential, and free electron concentration are analyzed in different nanowire regions to investigate the device's performance. The results show good performance despite the high density of deep states in poly-SiNW. This can be explained by the strong electric field caused by the corner effect in the nanowire, which favors the ionization of the acceptor traps and increases the free electron concentration. [ABSTRACT FROM AUTHOR]

This analytical modeling study delves into the resonance behavior of plasma waves within the channel of High Electron Mobility Transistors (HEMTs) when subjected to Terahertz (THz) excitation. The core objective is to systematically examine the influence of various HEMT parameters on the dynamics of plasma resonance and the detection of THz signals. A noteworthy finding emerges: the most effective detection of THz signals materializes when both the gate and drain terminals simultaneously receive the THz excitation. Moreover, the modulation of biasing conditions, specifically represented by polarization voltages, exerts a substantial influence on plasma resonance frequencies, offering a promising avenue for tailoring HEMT responses. Further exploration reveals the substantial impact of access region characteristics, including length and doping concentration, on the excitation of 3D plasma waves within the HEMT, with the drain access region demonstrating particular significance. Additionally, we delve into the ramifications of gate geometry, encompassing width and channel-to-gate distance, revealing their capacity to significantly alter 2D plasma resonance frequencies. In extreme cases, the HEMT exhibits behavior akin to a simplified diode configuration, resulting in the absence of 2D plasma resonance. In summation, this research unfolds essential insights for the design and optimization of HEMT-based devices tailored to specific THz frequency applications. It underscores the pivotal roles of biasing conditions, access region properties, and gate geometries in shaping HEMT performance and THz signal detection. [ABSTRACT FROM AUTHOR]

Graphene, renowned for its exceptional electrical, optical, and mechanical properties, takes center stage in the realm of next-generation electronics. In this paper, we provide a thorough investigation into the comprehensive fabrication process of graphene field-effect transistors. Recognizing the pivotal role graphene quality plays in determining device performance, we explore many techniques and metrological methods to assess and ensure the superior quality of graphene layers. In addition, we delve into the intricate nuances of doping graphene and examine its effects on electronic properties. We uncover the transformative impact these dopants have on the charge carrier concentration, bandgap, and overall device performance. By amalgamating these critical facets of graphene field-effect transistors fabrication and analysis, this study offers a holistic understanding for researchers and engineers aiming to optimize the performance of graphene-based electronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional material indium selenide (InSe) holds great promise for applications in electronics and optoelectronics by virtue of its fascinating properties. However, most multilayer InSe-based transistors suffer from extrinsic scattering effects from interface disorders and the environment, which cause carrier mobility and density fluctuations and hinder their practical application. In this work, we employ the non-destructive method of van der Waals (vdW) integration to improve the electron mobility of back-gated multilayer InSe FETs. After introducing the hexagonal boron nitride (h-BN) as both an encapsulation layer and back-gate dielectric with the vdW interface, as well as graphene serving as a buffer contact layer, the electron mobilities of InSe FETs are substantially enhanced. The vdW-integrated devices exhibit a high electron mobility exceeding 103 cm2 V−1 s−1 and current on/off ratios of ~108 at room temperature. Meanwhile, the electron densities are found to exceed 1012 cm−2. In addition, the fabricated devices show an excellent stability with a negligible electrical degradation after storage in ambient conditions for one month. Electrical transport measurements on InSe FETs in different configurations suggest that a performance enhancement with vdW integration should arise from a sufficient screening effect on the interface impurities and an effective passivation of the air-sensitive surface. [ABSTRACT FROM AUTHOR]

Abstract The rapid advancement of wearable biosensors has revolutionized healthcare monitoring by screening in a non-invasive and continuous manner. Among various sensing techniques, field-effect transistor (FET)-based wearable biosensors attract increasing attention due to their advantages such as label-free detection, fast response, easy operation, and capability of integration. This review explores the innovative developments and applications of FET-based wearable biosensors for healthcare monitoring. Beginning with an introduction to the significance of wearable biosensors, the paper gives an overview of structural and operational principles of FETs, providing insights into their diverse classifications. Next, the paper discusses the fabrication methods, semiconductor surface modification techniques and gate surface functionalization strategies. This background lays the foundation for exploring specific FET-based biosensor designs, including enzyme, antibody and nanobody, aptamer, as well as ion-sensitive membrane sensors. Subsequently, the paper investigates the incorporation of FET-based biosensors in monitoring biomarkers present in physiological fluids such as sweat, tears, saliva, and skin interstitial fluid (ISF). Finally, we address challenges, technical issues, and opportunities related to FET-based biosensor applications. This comprehensive review underscores the transformative potential of FET-based wearable biosensors in healthcare monitoring. By offering a multidimensional perspective on device design, fabrication, functionalization and applications, this paper aims to serve as a valuable resource for researchers in the field of biosensing technology and personalized healthcare.

Field effect transistor (FET) has attracted high attention in biomolecules detection. However, the sensitivity of FET-based biosensors is often limited by the charge screening effect. In addition, the facile and ultra-sensitive detection for small biomolecules, which possess weak charge or electroneutral, remains to be studied. Here, the self-assembled monolayer AuNPs/three-dimensional (3D) crumpled graphene FET is structured for a biosensor by shrinking flexible polystyrene (PS) films through heat treatment method and realized label-free and ultra-sensitive detection of dopamine (DA) using DA aptamer as probes immobilized on the AuNPs/3D crumpled graphene surface. The nanoscale deformation caused by thermal expansion effect of flexible graphene/PS can effectively reduce charge screening and the synergistic application of crumpled graphene and AuNPs can promote electron transfer and the graphene carrier concentration, leading to conductivity increase and hydrophilicity enhancement of 3D graphene. In addition, the binding of DA aptamer to DA will cause conformational changes of the aptamer molecule, which affects the charge transport properties of the sensor, thus improving its selectivity and stability. The biosensor can also easily distinguish interfering substances for DA detection in complex components (PBS, human urine, and fetal calf serum) with the detection limits as low as 60, 240 and 316 zM (10−19–10−11 M), respectively. DA released from exocytosis induced by K+ stimulation was selectively detected. The results show that the biosensor can be used as an excellent tool for ultrasensitive molecular recognition and detecting the effects of exogenous reagents on living cells, which is promising for clinical diagnosis and early disease prevention.

Exhaled breath‐based disease diagnosis is an ancient technique, and the application of this technique is rapidly developing for disease quick testing, such as viral infection, asthma, chronic kidney disease, and so on. Among the diagnostic tools, an exhaled breath‐based test has demonstrated the merits of being non‐invasive, convenient, quick, and comfortable. In this review, the exhaled breath diagnosis via the gaseous part of the breath is the major focus. First, the summary of state‐of‐art studies based on exhaled gas detection is described. Second, typical disease‐related exhaled gas and their measurements are described. Finally, the various structure of field effect transistor (FET)‐type sensors for gas‐based disease detection is discussed in detail. This review may inspire new research ideas and directions for applying FET‐type sensors to quick disease detection via the gaseous route. [ABSTRACT FROM AUTHOR]

Highly oriented, single crystalline, quaternary alloy chalcogenide crystal, Mo x W1− x S2 y Se2(1− y), is synthesized using a high temperature chemical vapor transport technique and its transport properties studied over a wide temperature range. Field effect transistors (FET) with bottom gated configuration are fabricated using Mo0.5W0.5SSe flakes of different thicknesses, from a single layer to bulk. The FET characteristics are thickness tunable, with thin flakes (1–4 layers) exhibiting n-type transport behaviour while ambipolar transfer characteristics are observed for thicker flakes (>90 layers). Ambipolar behavior with the dominance of n-type over p-type transport is noted for devices fabricated with layers between 9 and 90. The devices with flake thickness ∼9 layers exhibit a maximum electron mobility 63 ± 4 cm2 V−1s−1 and an I ON/ I OFF ratio >108. A maximum hole mobility 10.3 ± 0.4 cm2 V−1s−1 is observed for the devices with flake thickness ∼94 layers with I ON/ I OFF ratio >102–103 observed for the hole conduction. A maximum I ON/ I OFF for hole conduction, 104 is obtained for the devices fabricated with flakes of thickness ∼7–19 layers. The electron Schottky barrier height values are determined to be ∼23.3 meV and ∼74 meV for 2 layer and 94 layers flakes respectively, as measured using low temperature measurements. This indicates that an increase in hole current with thickness is likely to be due to lowering of the band gap as a function of thickness. Furthermore, the contact resistance (R ct) is evaluated using transmission line model (TLM) and is found to be 14 kohm. μ m. These results suggest that quaternary alloys of Mo0.5W0.5SSe are potential candidates for various electronic/optoelectronic devices where properties and performance can be tuned within a single composition. [ABSTRACT FROM AUTHOR]

The rapid advancement of wearable biosensors has revolutionized healthcare monitoring by screening in a non-invasive and continuous manner. Among various sensing techniques, field-effect transistor (FET)-based wearable biosensors attract increasing attention due to their advantages such as label-free detection, fast response, easy operation, and capability of integration. This review explores the innovative developments and applications of FET-based wearable biosensors for healthcare monitoring. Beginning with an introduction to the significance of wearable biosensors, the paper gives an overview of structural and operational principles of FETs, providing insights into their diverse classifications. Next, the paper discusses the fabrication methods, semiconductor surface modification techniques and gate surface functionalization strategies. This background lays the foundation for exploring specific FET-based biosensor designs, including enzyme, antibody and nanobody, aptamer, as well as ion-sensitive membrane sensors. Subsequently, the paper investigates the incorporation of FET-based biosensors in monitoring biomarkers present in physiological fluids such as sweat, tears, saliva, and skin interstitial fluid (ISF). Finally, we address challenges, technical issues, and opportunities related to FET-based biosensor applications. This comprehensive review underscores the transformative potential of FET-based wearable biosensors in healthcare monitoring. By offering a multidimensional perspective on device design, fabrication, functionalization and applications, this paper aims to serve as a valuable resource for researchers in the field of biosensing technology and personalized healthcare. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) showed great potentials in 2D nanoelectronic devices due to their abundant and unique properties. The performance stability of the 2D TMDCs devices turns into one of the keys for their practical applications but has been rarely explored. Here, we investigated stability of MoS2 devices in ambient condition and contributed the device performance degradation to the surface oxidation of the contact metals with low work function, which increased the contact barrier and hindered the electron injection. We developed a new approach to recover the performance of the aged devices through the selective doping of contacts with organolithium, which prolonged the lifetime of MoS2 devices. Our work not only provides important insights into the stability of 2D TMDCs devices, but also opens up a new avenue for optimizing the performance of 2D MoS2 devices. [ABSTRACT FROM AUTHOR]

Abstract The authors’ present a silicon‐on‐insulator (SOI) laterally diffused metal‐oxide‐semiconductor field‐effect transistor (LDMOSFET) with β‐Ga2O3 , which is a large bandgap semiconductor (β‐LDMOSFET), for increasing breakdown voltage (VBR) and power figure of merit. The fundamental purpose is to use a β‐Ga2O3 semiconductor instead of silicon material due to its large breakdown field. The characteristics of β‐LDMOSFET are analysed to those of standard LDMOSFET, such as VBR, ON‐resistance (RON), power figure of merit (PFOM), and radio frequency (RF) performances. The effects of RF, such as gate‐drain capacitance (CGD), gate‐source capacitance (CGS), transit frequency (fT), and maximum frequency of oscillation (fMAX) have been investigated. The β‐LDMOSFET structure outperforms performance in the VBR by increasing it to 500 versus 84.4 V in standard LDMOSFET design. The suggested β‐LDMOSFET has RON ~ 2.3 mΩ.cm−2 and increased the PFOM (VBR2/RON) to 108.6 MW/cm2. All the simulations are done with TCAD and simulation models are calibrated with the experimental data.

Adenosine triphosphate (ATP) is closely related to the pathogenesis of certain diseases, so the detection of trace ATP is of great significance to disease diagnosis and drug development. Graphene field-effect transistors (GFETs) have been proven to be a promising platform for the rapid and accurate detection of small molecules, while the Debye shielding limits the sensitive detection in real samples. Here, a three-dimensional wrinkled graphene field-effect transistor (3D WG-FET) biosensor for ultra-sensitive detection of ATP is demonstrated. The lowest detection limit of 3D WG-FET for analyzing ATP is down to 3.01 aM, which is much lower than the reported results. In addition, the 3D WG-FET biosensor shows a good linear electrical response to ATP concentrations in a broad range of detection from 10 aM to 10 pM. Meanwhile, we achieved ultra-sensitive (LOD: 10 aM) and quantitative (range from 10 aM to 100 fM) measurements of ATP in human serum. The 3D WG-FET also exhibits high specificity. This work may provide a novel approach to improve the sensitivity for the detection of ATP in complex biological matrix, showing a broad application value for early clinical diagnosis and food health monitoring. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the advantages of high sensitivity, rapid response, label‐free, and simple operation, field effect transistor biosensors have shown promising application prospects in large‐scale pathogen screening. However, in practical biological fluids with relatively high ionic strength, such as saliva and serum, the Debye screening effect will weaken the interaction between FET biosensors and target bio‐molecules, thereby affecting the sensing sensitivity and accuracy. Herein, an interfacial polymer‐engineered field effect transistor (IPE FET) biosensor was developed for the efficient identification of SARS‐CoV‐2 N antigens in saliva samples. The inclusion of a polymer layer shortens the distance between target molecules and the electrode interface, which effectively overcomes the limitation of Debye screening. The constructed IPE FET biosensors exhibit high sensitivity and anti‐fouling capability, achieving efficient detection of SARS‐CoV‐2 N antigen in saliva within 5 min with a detection limit of 4.6 fg·mL−1. In a cohort of 35 simulated throat swab samples of SARS‐CoV‐2 N antigen, IPE FET exhibits an identification accuracy of up to 97.1%, with predictive sensitivity and specificity of 96.0% and 100.0%, respectively. The excellent performance of IPE FET not only provides a strategy to design efficient detection platforms but also suggests a pathway to realize rapid and scalable epidemic screening. [ABSTRACT FROM AUTHOR]

Atomically thin narrow-bandgap layered PdSe2 has attracted much attention due to its rich and unique electrical properties. For silicon-compatible device integration, direct wafer-scale preparation of high-quality PdSe2 thin film on a silicon substrate is highly desired. Here, we present the low-temperature synthesis of large-area polycrystalline PdSe2 films grown on SiO2/Si substrates by plasma-assisted metal selenization and investigate their charge carrier transport behaviors. Raman analysis, depth-dependent x-ray photoelectron spectroscopy, and cross-sectional transmission electron microscopy were used to reveal the selenization process. The results indicate a structural evolution from initial Pd to intermediate PdSe2– x phase and eventually to PdSe2. The field-effect transistors fabricated from these ultrathin PdSe2 films exhibit strong thickness-dependent transport behaviors. For thinner films (4.5 nm), a record high on/off ratio of 104 was obtained. While for thick ones (11 nm), the maximum hole mobility is about 0.93 cm2 V−1 S−1, which is the record high value ever reported for polycrystalline films. These findings suggest that our low-temperature-metal-selenized PdSe2 films have high quality and show great potential for applications in electrical devices. [ABSTRACT FROM AUTHOR]

Recently, electronic devices that make use of a state called the electric double layers (EDL) of ion have opened up a wide range of research opportunities, from novel physical phenomena in solid‐state materials to next‐generation low‐power consumption devices. They are considered to be the future iontronics devices. EDLs behave as nanogap capacitors, resulting the high density of charge carriers is induced at semiconductor/electrolyte by applying only a few volts of the bias voltage. This enables the low‐power operation of electronic devices as well as new functional devices. Furthermore, by controlling the motion of ions, ions can be used as semi‐permanent charge to form electrets. In this article, we are going to introduce the recent advanced application of iontronics devices as well as energy harvesters making use of ion‐based electrets, leading to the future iontronics research. [ABSTRACT FROM AUTHOR]

As conventional Complementary Metal Oxide Semiconductor (CMOS) reaches extreme limitation to implement the digital circuits with high density and low power dissipation, alternate devices are necessary. To keep Moore's Law alive and to implement the processors with tiny devices, the researchers are trying to produce nano-devices, alternatives to conventional devices. Nanowire is a most prominent device to replace the CMOS at nano-scale for the low-power digital technology among the emerging Nanodevices. Transistors designed with Nanowire structures achieve a tradeoff between the power and density to implement the digital circuits. This paper is focused on reviewing the details of the synthesis of nanowire, few dominant applications of the nanowire, and nanowire mechanics. Initially, the growth pattern and controlling the Nanowire dimensions are discussed under the synthesis of nanowire. This is followed by a brief overview of nano-photonics which plays a key role in optical communications. Further, the mechanical properties, applications of nanowire, and the gate structures are highlighted. [ABSTRACT FROM AUTHOR]

A spiral interdigitated MXene–assisted field effect transistor (SiMFETs) was proposed for determination of IL-6 in patients with kidney transplantation infection. Our SiMFETs demonstrated enhanced IL-6 detection range of 10 fg/mL–100 ng/mL due to the combination of optimized transistor's structure and semiconducting nanocomposites. Specifically, on one hand, MXene-based field effect transistor drastically amplified the amperometric signal for determination of IL-6; on the other hand, the multiple spiral structure of interdigitated drain-source architecture improved the transconductance of FET biosensor. The developed SiMFETs biosensor demonstrated satisfactory stability for 2 months, and favorable reproducibility and selectivity against other biochemical interferences. The SiMFETs biosensor exhibited acceptable correlation coefficient (R2=0.955) in quantification of clinical biosamples. The sensor successfully distinguished the infected patients from the health control with enhanced AUC of 0.939 (sensitivity of 91.7%, specificity of 86.7%). Those merits introduced here may pave an alternative strategy for transistor-based biosensor in point-of-care clinic applications. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDC) have been considered promising electronic materials in recent years. Annealing and chemical doping are two core processes used in manufacturing electronic devices to modify properties and improve device performance, where annealing enhances crystal quality, reduces defects, and enhances carrier mobility, while chemical doping modifies conductivity and introduces new energy levels within the bandgap. In this study, we investigate the annealing effects of various types of dopants, time, and ambient conditions on the diverse material properties of TMDCs, including crystal structure quality, defect density, carrier mobility, electronic properties, and energy levels within the bandgap. [ABSTRACT FROM AUTHOR]

Investigation of germanium gate hydrogen-terminated (H-terminated) diamond field effect transistor (FET) with Al2O3 dielectric layer has been successfully performed. The device demonstrates a normally-on characteristics, whose maximum drain-source current density, threshold voltage, maximum transconductance, on/off ratio, subthreshold swing, capacitance, carrier density, saturation carrier mobility, fixed charge density and interface state density are of −37.3 mA/mm, 0.22 V, 6.42 mS/mm, 108, 134 mV/dec, 0.33 μF/cm2, 9.83 × 1012 cm−2, 97.9 cm2/V·s, 7.63 × 1012 cm−2 and 2.56 × 1012 cm−2·eV−1, respectively. This work is significant to the development of H-terminated diamond FET.

Diamond field-effect transistor (FET) has great application potential for high frequency and high power electronic devices. In this work, diamond FETs were fabricated on (0 0 1) single crystal diamond with homoepitaxial layer. The nitrogen impurity content in the homoepitaxial layer is greatly decreased as measured by the Raman and photoluminescence spectra. The diamond field effect transistor with 100 nm Al2O3 as gate dielectric shows ohomic contact resistance of 35 Ω . mm, maximum drain saturation current density of 500 mA/mm, and maximum transconductance of 20.1 mS/mm. Due to the high quality of Al2O3 gate dielectric and single crystal diamond substrate, the drain work voltage of −58 V is achieved for the diamond FETs. A continuous wave output power density of 4.2 W/mm at 2 GHz is obtained. The output power densities at 4 and 10 GHz are also improved and achieve 3.1 and 1.7 W/mm, respectively. This work shows the application potential of single crystal diamond for high frequency and high power electronic devices.

Mass pathogen screening is critical to preventing the outbreaks and spread of infectious diseases. The large‐scale epidemic of COVID‐19 and the rapid mutation of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) virus have put forward new requirements for virus detection and identification techniques. Here, we report a CRISPR‐based Amplification‐free Viral RNA Electrical Detection platform (CAVRED) for the rapid detection and identification of SARS‐CoV‐2 variants. A series of CRISPR RNA assays were designed to amplify the CRISPR‐Cas system's ability to discriminate between mutant and wild RNA genomes with a single‐nucleotide difference. The identified viral RNA information was converted into readable electrical signals through field‐effect transistor biosensors for the achievement of highly sensitive detection of single‐base mutations. CAVRED can detect the SARS‐CoV‐2 virus genome as low as 1 cp μL−1 within 20 mins without amplification, and this value is comparable to the detection limit of real‐time quantitative polymerase chain reaction. Based on the excellent RNA mutation detection ability, an 8‐in‐1 CAVRED array was constructed and realized the rapid identification of 40 simulated throat swab samples of SARS‐CoV‐2 variants with a 95.0 % accuracy. The advantages of accuracy, sensitivity, and fast speed of CAVRED promise its application in rapid and large‐scale epidemic screening. [ABSTRACT FROM AUTHOR]

The contact electrodes have great influence on the performance of monolayer MoS2 devices. In this paper, monolayer MoS2 and MoS2 nanobelts were synthesized on SiO2/Si substrates via the chemical vapor deposition method. By using wet and dry transfer process, MoS2 nanobelt metallic edges were designed as the source/drain contact electrodes of monolayer MoS2 field effect transistor. The 'nanobelt metallic edges' refers to the top surface of the nanobelt being metallic. Because the base planes of MoS2 nanobelt vertically stand on the substrate, which makes the layer edges form the top surface of the nanobelt. The nonlinear I ds– V ds characteristics of the device indicates that the contact between the monolayer MoS2 and MoS2 metallic edges displays a Schottky-like behavior. The back-gated transfer characteristics indicate that monolayer MoS2 device with MoS2 nanobelt metallic edges as electrodes shows an n-type behavior with a mobility of ∼0.44 cm2 V−1·s−1, a carrier concentration of ∼7.31 × 1011 cm−2, and an on/off ratio of ∼103. The results enrich the electrode materials of two-dimensional material devices and exhibit potential for future application of MoS2 metallic edges in electronic devices. [ABSTRACT FROM AUTHOR]

The upgrading of useful biosensors having advantages in disease monitoring besides detection has been sped up by the demand for quick, cheap, portable, easy screening procedures. Bioanalytical devices such as Biosensors have a number of distinguishing benefits over conventional analytical techniques, including high accuracy and specificity, ease of handling, economic friendly, and the potential for downsizing and mass production. With an emphasis on electrochemical and optical sensors, this study examines current developments in the design, performance, and applications of biosensors. Due to its advantages of high sensitivity, specificity, and rapid analysis, electrochemical sensors have demonstrated a wide range of applications in biological detection whereas the optical biosensors covered in this article have enabled diagnosis of SARS-CoV-2, which highlighted the importance of creating swift and extremely sensitive diagnostic methods for quickly identifying infected patients using LSPR, SERS, FET, EC biosensors. [ABSTRACT FROM AUTHOR]

Sensitive detection of nitrogen dioxide (NO2) is of significance in many areas for health and environmental protections. In this work, we developed an efficient NO2 sensor that can respond within seconds at room temperature, and the limit of detection (LOD) is as low as 100 ppb. Coating cyano-substituted poly(p-phenylene vinylene) (CN-PPV) films on graphene (G) layers can dope G sheets effectively to a heavy n state. The influences of solution concentrations and annealing temperatures on the n-doping effect were investigated in detail. The CN-PPV–G transistors fabricated with the optimized parameters demonstrate active sensing abilities toward NO2. The n-doping state of CN-PPV–G is reduced dramatically by NO2, which is a strong p-doping compound. Upon exposure to 25 ppm of NO2, our CN-PPV–G sensors react in 10 s, indicating it is almost an immediate response. LOD is determined as low as 100 ppb. The ultrahigh responding speed and low LOD are not affected in dry air. Furthermore, cycling use of our sensors can be realized through simple annealing. The superior features shown by our CN-PPV–G sensors are highly desired in the applications of monitoring the level of NO2 in situ and setting immediate alarms. Our results also suggest that transfer curves of transistors can react very promptly to the stimulus of target gas and, thus, are very promising in the development of fast-response sensing devices although the response values may not reach maximum as a tradeoff. [ABSTRACT FROM AUTHOR]

The authors' present a silicon‐on‐insulator (SOI) laterally diffused metal‐oxide‐semiconductor field‐effect transistor (LDMOSFET) with β‐Ga2O3 , which is a large bandgap semiconductor (β‐LDMOSFET), for increasing breakdown voltage (VBR) and power figure of merit. The fundamental purpose is to use a β‐Ga2O3 semiconductor instead of silicon material due to its large breakdown field. The characteristics of β‐LDMOSFET are analysed to those of standard LDMOSFET, such as VBR, ON‐resistance (RON), power figure of merit (PFOM), and radio frequency (RF) performances. The effects of RF, such as gate‐drain capacitance (CGD), gate‐source capacitance (CGS), transit frequency (fT), and maximum frequency of oscillation (fMAX) have been investigated. The β‐LDMOSFET structure outperforms performance in the VBR by increasing it to 500 versus 84.4 V in standard LDMOSFET design. The suggested β‐LDMOSFET has RON ~ 2.3 mΩ.cm−2 and increased the PFOM (VBR2/RON) to 108.6 MW/cm2. All the simulations are done with TCAD and simulation models are calibrated with the experimental data. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots of perovskites having the chemical composition CsPbBr3 have been synthesized. For these particles, the average size of an ensemble of particles and sample polydispersity have been determined by steady-state spectrofluorometry. Conducting layers were made from the obtained particles, and the electrophysical characteristics of these layers were measured. The hole nature of the conductivity was established, and the layer conductivity (0.04 S/m), mobility (0.8 cm2/(V s)), and number concentration of free charge carriers (3.01 × 1021 m−3) were measured. In accordance with published data, the measured mobility value is higher by one to two orders of magnitude than published typical values. It is shown that high polydispersity has a weak effect on the electrophysical and transport characteristics in the resulting layers. [ABSTRACT FROM AUTHOR]

Human epidermal growth factor receptor-3 (HER-3) plays a key role in the growth and metastasis of cancer cells. The detection of HER-3 is very important for early screening and treatment of cancer. The AlGaN/GaN-based ion-sensitive heterostructure field effect transistor (ISHFET) is sensitive to surface charges. This makes it a promising candidate for the detection of HER-3. In this paper, we developed a biosensor for the detection of HER-3 with AlGaN/GaN-based ISHFET. The AlGaN/GaN-based ISHFET biosensor exhibits a sensitivity of 0.53 ± 0.04 mA/dec in 0.01 M phosphate buffer saline (1× PBS) (pH = 7.4) solution with 4% bovine serum albumin (BSA) at a source and drain voltage of 2 V. The detection limit is 2 ng/mL. A higher sensitivity (2.20 ± 0.15 mA/dec) can be achieved in 1× PBS buffer solution at a source and drain voltage of 2 V. The AlGaN/GaN-based ISHFET biosensor can be used for micro-liter (5 μL) solution measurements and the measurement can be performed after incubation of 5 min. [ABSTRACT FROM AUTHOR]

An ideal biosensor material at room temperature, with an extremely large surface area per unit mass combined with the possibility of harnessing quantum mechanical attributes, would be comprised of graphene and other two-dimensional (2D) materials. The sensing of a variety of sizes and types of biomolecules involves modulation of the electrical charge density of (current through) the 2D material and manifests through specific components of the capacitance (resistance). While sensitive detection at the single-molecule level, i.e., at zeptomolar concentrations, may be achieved, specificity in a complex mixture is more demanding. Attention should be paid to the influence of inevitably present defects in the 2D materials on the sensing, as well as calibration of obtained results with acceptable standards. The consequent establishment of a roadmap for the widespread deployment of 2D material–based biosensors in point-of-care platforms has the potential to revolutionize health care. [ABSTRACT FROM AUTHOR]

Previous breakthroughs in biosensor diagnostics stem from engineering and nanocomposites. Accurately detecting low-abundance compounds such as methotrexate in complex biospecimens (e.g. serum) is an important clinical challenge. To address this issue, a MWCNTs-doped MXene-based multi-spiral-channel field-effect transistor (MMSFETs) biosensor was constructed for ultrasensitive quantification of methotrexate. Our integrated biosensor exhibited following merits: a) The synergetic performance of MXene and MWCNTs for enhanced transconductance (0.63 mS) and detection capability (methotrexate, linear range of 0.001–100 μM and LOD down to 0.352 nM); b) Favorable selectivity, stability (one month), reproducibility (RSD = 0.99%, n = 7) for biosensing of methotrexate; c) Acceptable clinical performances on comparisons of MMFETs against commercial Abbott automatic immunoluminescence instrument (ARCHITECT I1000): favorable linearity and correlation coefficient (YMMSFETs = 1.4305 × Xtargeted concentration + 4.3791 with R2 = 0.949), significant p value (7.68E-12

Graphene, renowned for its exceptional electrical, optical, and mechanical properties, takes center stage in the realm of next-generation electronics. In this paper, we provide a thorough investigation into the comprehensive fabrication process of graphene field-effect transistors. Recognizing the pivotal role graphene quality plays in determining device performance, we explore many techniques and metrological methods to assess and ensure the superior quality of graphene layers. In addition, we delve into the intricate nuances of doping graphene and examine its effects on electronic properties. We uncover the transformative impact these dopants have on the charge carrier concentration, bandgap, and overall device performance. By amalgamating these critical facets of graphene field-effect transistors fabrication and analysis, this study offers a holistic understanding for researchers and engineers aiming to optimize the performance of graphene-based electronic devices.