Layer In Field-effect Transistors Research Articles

Colloidal Synthesis of P-Type Zn3 As2 Nanocrystals.

Zinc pnictides, particularly Zn3 As2 , hold significant promise for optoelectronic applications owing to their intrinsic p-type behavior and appropriate bandgaps. However, despite the outstanding properties of colloidal Zn3 As2 nanocrystals, research in this area is lacking because of the absence of suitable precursors, occurrence of surface oxidation, and intricacy of the crystal structures. In this study, a novel and facile solution-based synthetic approach is presented for obtaining highly crystalline p-type Zn3 As2 nanocrystals with accurate stoichiometry. By carefully controlling the feed ratio and reaction temperature, colloidal Zn3 As2 nanocrystals are successfully obtained. Moreover, the mechanism underlying the conversion of As precursors in the initial phases of Zn3 As2 synthesis is elucidated. Furthermore, these nanocrystals are employed as active layers in field-effect transistors that exhibit inherent p-type characteristics with native surface ligands. To enhance the charge transport properties, a dual passivation strategy is introduced via phase-transfer ligand exchange, leading to enhanced hole mobilities as high as 0.089 cm2 V-1 s-1 . This study not only contributes to the advancement of nanocrystal synthesis, but also opens up new possibilities for previously underexplored p-type nanocrystal research.

Periphery Fusion Strategy of a Carbazole-Based Macrocycle toward Coplanar N-Heterocycloarene for High-Mobility Single-Crystal Transistors.

Designing (hetero)cycloarenes through the modifications of the π-topology and molecular packing of organic semiconductors has recently garnered considerable attention. However, their applications as an organic active layer in field-effect transistors are very limited, and the obtained hole carrier mobilities are less than 1 cm2 V-1 s-1 . In this work, a novel alkyl-substituted coplanar N-heterocycloarene (FM-C4) containing four carbazole units is successfully synthesized in crystalline form. As compared to the corresponding single-bond-linked carbazole-based macrocycle M-C4, it is found that the periphery fusion strategy greatly changes the electronic structures, energy levels, photophysical properties, host-guest interactions with fullerenes, and molecular crystal stacking motifs. In particular, the fully fused N-heterocycloarene FM-C4 exhibits a herringbone packing structure with an unusual long-range π-π overlap distance as low as 3.19 Å, whereas the single crystal of M-C4 demonstrates no π-π interactions. As a consequence, FM-C4 in single-crystal transistors displays the highest hole mobility of 2.06 cm2 V-1 s-1 , significantly outperforming M-C4 and all the reported (hetero)cycloarenes and suggesting the high potential of (hetero)cycloarenes for organic electronic applications.

Combination of Polymer Gate Dielectric and Two-Dimensional Semiconductor for Emerging Field-Effect Transistors

Two-dimensional (2D) materials are considered attractive semiconducting layers for emerging field-effect transistors owing to their unique electronic and optoelectronic properties. Polymers have been utilized in combination with 2D semiconductors as gate dielectric layers in field-effect transistors (FETs). Despite their distinctive advantages, the applicability of polymer gate dielectric materials for 2D semiconductor FETs has rarely been discussed in a comprehensive manner. Therefore, this paper reviews recent progress relating to 2D semiconductor FETs based on a wide range of polymeric gate dielectric materials, including (1) solution-based polymer dielectrics, (2) vacuum-deposited polymer dielectrics, (3) ferroelectric polymers, and (4) ion gels. Exploiting appropriate materials and corresponding processes, polymer gate dielectrics have enhanced the performance of 2D semiconductor FETs and enabled the development of versatile device structures in energy-efficient ways. Furthermore, FET-based functional electronic devices, such as flash memory devices, photodetectors, ferroelectric memory devices, and flexible electronics, are highlighted in this review. This paper also outlines challenges and opportunities in order to help develop high-performance FETs based on 2D semiconductors and polymer gate dielectrics and realize their practical applications.

Alkali-Doped Nanopaper Membranes Applied as a Gate Dielectric in FETs and Logic Gates with an Enhanced Dynamic Response.

The market for flexible, hybrid, and printed electronic systems, which can appear in everything from sensors and wearables to displays and lighting, is still uncertain. What is clear is that these systems are appearing every day, enabling devices and systems that can, in the near future, be crumpled up and tucked in our pockets. Within this context, cellulose-based modified nanopapers were developed to serve both as a physical support and a gate dielectric layer in field-effect transistors (FETs) that are fully recyclable. It was found that the impregnation of those nanopapers with sodium (Na+) ions allows for low operating voltage FETs (<3 V), with mobility above 10 cm2 V-1 s-1, current modulation surpassing 105, and an improved dynamic response. Thus, it was possible to implement those transistors into simple circuits such as inverters, reaching a clear discrimination between logic states. Besides the overall improvement in electrical performance, these devices have shown to be an interesting alternative for reliable, sustainable, and flexible electronics, maintaining proper operation even under stress conditions.

Exploring the Role of 2D-Graphdiyne as a Charge Carrier Layer in Field-Effect Transistors for Non-Covalent Biological Immobilization against Human Diseases.

Graphdiyne's (GDY's) outstanding features have made it a novel 2D nanomaterial and a great candidate for electronic gadgets and optoelectronic devices, and it has opened new opportunities for the development of highly sensitive electronic and optical detection methods as well. Here, we testified a non-covalent grafting strategy in which GDY serves as a charge carrier layer and a bioaffinity substrate to immobilize biological receptors on GDY-based field-effect transistor (FET) devices. Firm non-covalent anchoring of biological molecules via pyrene groups and electrostatic interactions in addition to preserved electrical properties of GDY endows it with features of an ultrasensitive and stable detection mechanism. With emerging new forms and extending the subtypes of the already existing fatal diseases, genetic and biological knowledge demands more details. In this regard, we constructed simple yet efficient platforms using GDY-based FET devices in order to detect different kinds of biological molecules that threaten human health. The resulted data showed that the proposed non-covalent bioaffinity assays in GDY-based FET devices could be considered reliable strategies for novel label-free biosensing platforms, which still reach a high on/off ratio of over 104. The limits of detection of the FET devices to detect DNA strands, the CA19-9 antigen, microRNA-155, the CA15-3 antigen, and the COVID-19 antigen were 0.2 aM, 0.04 pU mL-1, 0.11 aM, 0.043 pU mL-1, and 0.003 fg mL-1, respectively, in the linear ranges of 1 aM to 1 pM, 1 pU mL-1 to 0.1 μU mL-1, 1 aM to 1 pM, 1 pU mL-1 to 10 μU mL-1, and 1 fg mL-1 to 10 ng mL-1, respectively. Finally, the extraordinary performance of these label-free FET biosensors with low detection limits, high sensitivity and selectivity, capable of being miniaturized, and implantability for in vivo analysis makes them a great candidate in disease diagnostics and point-of-care testing.

Exploring the Role of 2d-Graphdiyne as Charge Carrier Layer in Field Effect Transistors for Non-Covalent Biological Immobilization Against Human Diseases

Exploring the Role of 2d-Graphdiyne as Charge Carrier Layer in Field Effect Transistors for Non-Covalent Biological Immobilization Against Human Diseases

Strategic Approach for Enhancing Sensitivity of Ammonia Gas Detection: Molecular Design Rule and Morphology Optimization for Stable Radical Anion Formation of Rylene Diimide Semiconductors

AbstractHerein, a strategic approach to enhance the sensitivity of ammonia gas detection using organic semiconductors by boosting the efficiency of ammonia gas‐induced stable radical anion formation (SRAF) is reported. This is achieved through rational molecular design and engineering of field‐effect transistors (FETs). New rylene diimide derivatives are designed and used to prepare molecular templates for efficient SRAF in thin films, and they are applied as gas‐adsorbing active layers in FETs. Substituting linear‐shaped perfluoroalkyl (PF) groups to π‐electron‐deficient naphthalene diimide (NDI) backbone enhances the ammonia gas detection limit to 200 ppb, attributed to the strong electron‐withdrawing capability and low steric hindrance of PF groups. Replacing the core backbone (NDI) with perylene diimide (PDI) while retaining the PF group further enhances gas‐responsivity up to 18.17 (1700% increase in current) due to the enlarged π‐conjugated bridge area. Computational characterization further supports that high electron affinity of the PDI‐PF molecules and a larger gas‐adsorption area in the PDI core result in the exceptional ammonia gas sensitivity. In addition, beneficial molecular orientation and nanopore formation of PDI‐PF facilitate gas adsorption, resulting in remarkably enhanced gas‐responsivity. The results indicate that molecular engineering for high‐efficiency SRAF suggests a new strategy for developing high‐sensitivity ammonia sensing platforms.

Phenanthroline Additives for Enhanced Semiconducting Carbon Nanotube Dispersion Stability and Transistor Performance

Dispersions of purely semiconducting single-walled carbon nanotubes (SWCNTs) have enabled solution-processed SWCNT networks as active layers in field-effect transistors (FETs) with high carrier mob...

Electric Double Layer Field Effect Transistor Using SnS Thin Film as Semiconductor Channel Layer and Honey Gate Dieletric

The study aimed at the investigation and application of SnS thin film semiconductor as a channel layer semiconductor in the assembly of an electric double layer field effect transistor which is important for the achievement and development of novel device concepts, applications and tuning of physical properties of materials since the reported EDLFET and the modulation of electronic states have so far been realised on oxides, nitrides, carbon nanotubes and organic semiconductor but has been rarely reported for the chalcogenides. Honey was used as a gel like electrolytic gate dielectric to generate an enhanced electric field response over SnS semiconductor channel layer and due to its ability to produces high on-current and low voltage operation while forming an ionic gel-like solution similar to ionic gels which consist of ionic liguids. SnS gated honey Electric double layer field effect transistor was assembled using tin sulphide (SnS) thin film as semiconductor channel layer and honey as gate dielectric. The measured gate capacitance of honey using LCR meter was measured as 2.15 μF/ cm2 while the dielectric constant is 20.50. The semiconductor layer was deposited using Aerosol assisted chemical vapour deposition and annealed in open air at 250 on an etched region about the middle of a 4×4 mm FTO glass substrate with the source and drain electrode region defined by the etching and masking at the two ends of the substrate. Iridium was used as the gate electrode while a copper wire was masked to the source and drain region to create electrode contact. The Profilometry, X-ray diffraction, Scanning electron microscope, Energy dispersive X-ray spectroscopy, Hall Effect measurement and digital multimeters were used to characterise the device. The SnS thin film was found to be polycrystalline consisting of Sn and S elements with define grains, an optical band of 1.42 eV and of 0.4 μm thickness. The transistor operated with a p type channel conductivity in a depletion mode with a field effect mobility of 16.67 cm2/Vs, cut-off voltage of 1.6 V, Drain saturation current of1.35μA, a transconductance of -809.61 nA/V and a sub threshold slope of -1.6 Vdec-1 which is comparable to standard specifications in Electronics Data sheets. Positive gate bias results in a shift in the cut off voltage due to charge trapping in the channel/dielectric interface.

Electric Double Layer Field-Effect Transistors Using Two-Dimensional (2D) Layers of Copper Indium Selenide (CuIn7Se11)

Innovations in the design of field-effect transistor (FET) devices will be the key to future application development related to ultrathin and low-power device technologies. In order to boost the current semiconductor device industry, new device architectures based on novel materials and system need to be envisioned. Here we report the fabrication of electric double layer field-effect transistors (EDL-FET) with two-dimensional (2D) layers of copper indium selenide (CuIn7Se11) as the channel material and an ionic liquid electrolyte (1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6)) as the gate terminal. We found one order of magnitude improvement in the on-off ratio, a five- to six-times increase in the field-effect mobility, and two orders of magnitude in the improvement in the subthreshold swing for ionic liquid gated devices as compared to silicon dioxide (SiO2) back gates. We also show that the performance of EDL-FETs can be enhanced by operating them under dual (top and back) gate conditions. Our investigations suggest that the performance of CuIn7Se11 FETs can be significantly improved when BMIM-PF6 is used as a top gate material (in both single and dual gate geometry) instead of the conventional dielectric layer of the SiO2 gate. These investigations show the potential of 2D material-based EDL-FETs in developing active components of future electronics needed for low-power applications.

Аномальное поведение боковой C-V-характеристики МНОП-транзистора со встроенным локальным зарядом в нитридном слое

C-V dependence of lateral source-base transition of metal-nitride-oxide-semiconductor field effect transistor with localized nitride trapped charge is simulated. Localizing the charge induce anomalous jumping or recession of the capacitance at defined applied voltage. The change of capacitance is connected with redistribution of carriers at semiconductor surface induced by charge trapping. The anomalous behaviour of the capacitance can be used at detecting the localized charge trapped in the dielectric layer of field effect transistors.

Triboiontronic Transistor of MoS2

Electric double layers (EDLs) formed in electrolyte-gated field-effect transistors (FETs) induce an extremely large local electric field that gives a highly efficient charge carrier control in the semiconductor channel. To achieve highly efficient triboelectric potential gating on the FET and explore diversified applications of electric double layer FETs (EDL-FETs), a triboiontronic transistor is proposed to bridge triboelectric potential modulation and ion-controlled semiconductor devices. Utilizing the triboelectric potential instead of applying an external gate voltage, the triboiontronic MoS2 transistor is efficiently operated owing to the formation of EDLs in the ion-gel dielectric layer. The operation mechanism of the triboiontronic transistor is proposed, and high current on/off ratio over 107 , low threshold value (75 μm), and steep switching properties (20 µm dec-1 ) are achieved. A triboiontronic logic inverter with desirable gain (8.3 V mm-1 ), low power consumption, and high stability is also demonstrated. This work presents a low-power-consuming, active, and a general approach to efficiently modulate semiconductor devices through mechanical instructions, which has great potential in human-machine interaction, electronic skin, and intelligent wearable devices. The proposed triboiontronics utilize ion migration and arrangement triggered by mechanical stimuli to control electronic properties, which are ready to deliver new interdisciplinary research directions.

Enhancing photoresponse by synergy of electric double layer gate and illumination in single CuTCNQ NW field effect transistors

&lt;p class="BodyText1"&gt;&lt;span lang="EN-IN"&gt;We report that photoresponse of &lt;/span&gt;&lt;span lang="EN-US"&gt;a single metal-organic charge transfer complex Cu:TCNQ nanowire (NW)&lt;/span&gt;&lt;span lang="EN-IN"&gt; can be enhanced simultaneously by illumination as well as applying a gate bias in an Electric Double Layer Field Effect Transistor (EDL-FET) configuration fabricated on &lt;/span&gt;&lt;span lang="EN-US"&gt;Cu:TCNQ &lt;/span&gt;&lt;span lang="EN-IN"&gt;as a channel.&lt;/span&gt;&lt;span lang="EN-IN"&gt;It is observed that applying a bias using an EDL gate to a n-channel Cu:TCNQ single NW FET, one can enhance the photoresponse of the Cu:TCNQ substantially over that which arise from the photoconductive response alone. &lt;/span&gt;&lt;span lang="EN-US"&gt;Electron-hole pairs that generate in the NW under illuminated of wavelength 400nm gives rise photo current. Also, electric double layer induce negative charges in the NW channel which effectively increases the carrier concentration, contributing to better response in conduction. &lt;/span&gt;&lt;span lang="EN-IN"&gt;The effect reported here has a generic nature that gives rise to a class of gated photodetectors of different photoresponsive materials.&lt;/span&gt;&lt;/p&gt;

Increased electrical conductivity of peptides through annealing process

Biocompatible biologically occurring polymer is suggested as a component of human implantable devices since conventional inorganic materials are apt to trigger inflammation and toxicity problem within human body. Peptides consisting of aromatic amino acid, tyrosine, are chosen, and enhancement on electrical conductivity is studied. Annealing process gives rise to the decrease on resistivity of the peptide films and the growth of the carrier concentration is a plausible reason for such a decrease on resistivity. The annealed peptides are further applied to an active layer of field effect transistor, in which low on/off current ratio (∼10) is obtained.

イオン液体/ルブレン単結晶界面の周波数変調AFMによる構造解析

The structural properties of ionic liquid/rubrene single-crystal interfaces were investigated using frequency modulation atomic force microscopy. The spontaneous dissolution of rubrene molecules into the ionic liquid was triggered by surface defects such as an oxidized rubrene or a vacancy, leading to the formation of a clean interface irrespective of the initial conditions. Force curve measurements revealed that a few solvation layers of ionic liquid molecules formed at the interface. We have also measured electric characteristics of electric double layer field-effect transistor based on the ionic liquid/rubrene single crystal interfaces. In contrast to usual devices, the mobility of field induced career was found to gradually increase with time for a day, consistent with the time scale of the spontaneous dissolution. These specific properties are discussed with respect to the microscopic understanding of electric double-layer transistors.

N-Type Superconductivity in an Organic Mott Insulator Induced by Light-Driven Electron-Doping.

The presence of interface dipoles in self-assembled monolayers (SAMs) gives rise to electric-field effects at the device interfaces. SAMs of spiropyran derivatives can be used as photoactive interface dipole layer in field-effect transistors because the photochromism of spiropyrans involves a large dipole moment switching. Recently, light-induced p-type superconductivity in an organic Mott insulator, κ-(BEDT-TTF)2 Cu[N(CN)2 ]Br (κ-Br: BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) has been realized, thanks to the hole carriers induced by significant interface dipole variation in the spiropyran-SAM. This report explores the converse situation by designing a new type of spiropyran monolayer in which light-induced electron-doping into κ-Br and accompanying n-type superconducting transition have been observed. These results open new possibilities for novel electronics utilizing a photoactive SAMs, which can design not only the magnitude but also the direction of photoinduced electric-fields at the device interfaces.

Uniform electroactive fibre-like micelle nanowires for organic electronics

Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications.

Laterally grown show better performance: ZnO nanorods network based field effect transistors

In this work, ZnO based field effect transistors have been demonstrated using self-aligned nanorods (NRs) network synthesized through a facile hydrothermal route. To control the alignment and orientation of nanorods two additives viz. Potassium Permanganate (KMnO4) and Potassium Dichromate (K2Cr2O7) were added into the precursor solution. The effect of additive was studied through structural and optical characterization of nanorods. Further, these nanorods were used as an active layer in field effect transistors (FETs) and the estimated field effect mobility and current on/off ratio of the devices were 0.56 × 10−4 cm2/V s and 10 for vertically aligned and 9.04 cm2/V s and 6 × 103 for laterally aligned NRs network respectively. It was observed that the transport properties of charges are associated with the alignment, size, interface junctions of NRs/NRs or NRs/electrode and trap defects/states on the surface. The possible mechanism of charge transport in network path has been systematically discussed.

Diamond based field-effect transistors with SiNx and ZrO2 double dielectric layers

A diamond-based field-effect transistor (FET) with SiNx and ZrO2 double dielectric layer has been demonstrated. The SiNx and ZrO2 gate dielectric are deposited by plasma-enhanced chemical vapor deposition (PECVD) and radio frequency (RF) sputter methods, respectively. SiNx layer is found to have the ability to preserve the conduction channel at the surface of hydrogen-terminated diamond film. The leakage current density (J) of SiNx/ZrO2 diamond metal-insulator-semiconductor FET (MISFET) keeps lower than 3.88×10−5A·cm−2 when the gate bias was changed from 2V to −8V. The double dielectric layer FET operates in a p-type depletion mode, whose maximum drain-source current, threshold voltage, maximum transconductance, effective mobility and sheet hole density are determined to be −28.5mA·mm−1, 2.2V, 4.53mS·mm−1, 38.9cm2·V−1·s−1, and 2.14×1013cm−2, respectively.

Gradual improvements of charge carrier mobility at ionic liquid/rubrene single crystal interfaces

We report evolution of electric characteristics of an electric double layer field-effect transistor based on the ionic liquid/rubrene single crystal interfaces. In contrast to usual devices, the field effect mobility was found to gradually increase with time for a day, followed by minor long-term fluctuations. Although the details of the evolution were somewhat device dependent, the final values of the mobility turned out to be 3–4 times larger irrespective of the initial values. These observations are explained by the evolution of the flat interface by defect-induced spontaneous dissolution of rubrene molecules at the ionic liquid/rubrene single crystal interfaces, revealed by frequency modulation atomic force microscopy.