Nanofiber Field-effect Transistors Research Articles

Ammonia gas sensors based on multi-wall carbon nanofiber field effect transistors by using gate modulation

Ammonia gas sensors play a critical role in environmental monitoring and healthcare applications due to the harmful effects of ammonia exposure. In this study, I present a novel approach to ammonia detection using field-effect transistors (FETs) based on Multi-Wall Carbon Nanofibers (MWCNFs), known for their outstanding electrical properties. I fabricate and characterize MWCNF-FET sensors, utilizing interdigitated Source-Drain electrodes directly deposited onto aligned semiconducting MWCNFs. By systematically investigating the effect of gate bias on sensor performance, I demonstrate that applying a positive gate voltage enhances the sensor's gas response by up to 55 % across varying concentrations of ammonia. Additionally, I show that appropriate gate modulation significantly improves the device's reversibility, ensuring reliable, repeatable measurements. These findings highlight the potential of MWCNF-FETs in developing high-performance, gate-tunable ammonia gas sensors for real-world applications.

Electrospun-Aligned Gd-Doped In2O3 Nanofiber Field-Effect Transistors for Artificial DNA Detection

In view of the time-consuming and laborious problem of detecting biological genetic information by conventional methods, it is important to study high-performance deoxyribonucleic acid (DNA) biosensors. In this report, an aligned Gd-doped In2O3 nanofiber favoring carrier transport was prepared by electrospinning. When the Gd doping concentration is 0.5 mol %, the aligned In2O3 nanofiber field-effect transistors (FETs) exhibit an excellent mobility (μ = 8.7 cm2/Vs), suitable threshold voltage (VTH = 0.3 V), large on/off current ratio (Ion/Ioff = 4.1 × 107), and outstanding stability. The FET biosensor based on one-dimensional nanofibers has the advantages of simple structure, fast response, high sensitivity, and extraordinary potential for biosensor applications, where the current variation is quite pronounced at concentrations as low as 10 nM DNA immobilized in the active layer of the aligned In1.995Gd0.005O3 nanofiber FET, and this phenomenon becomes more pronounced as the concentration of immobilized DNA increases. The sensing mechanism of the current variation is mainly attributed to the oxidation of guanine nucleotides in the DNA molecular chain. The aligned Gd-doped In2O3 nanofiber FETs exhibit high sensitivity to DNA at room temperature, which provides a solution for the development of novel DNA biosensors.

Highly sensitive and selective low-cost SnZrO nanofiber field-effect transistor for N,N-dimethylformamide vapour detection at room temperature

With the continuous attention to environmental issues, it is still a very important issue to study the gas sensor with high sensitivity, high selection and high stability at room temperature (28 ℃). In this work, we used electrospinning to prepare Zr-doped SnO2 nanofiber field-effect transistors (FETs). The mobility (μ) of SnZrO nanofiber field-effect transistors is 1.21 cm2/Vs and the threshold voltage (VTH) of 1.1 V. When used for the detection of N,N-dimethylformamide (DMF) vapour, the SnZrO nanofiber field-effect transistors exhibit excellent performance for DMF vapour at 28 ℃, including when the DMF vapour concentration is 500 ppb, the maximum response value is as high as 91.7; excellent gas selection characteristics; fast response and recovery time (57/10 s); low concentration (50 ppb) detection stability；low theoretical detection limit (1 ppb). In addition, capacitive-voltage (C-V) analysis is used to further explore the internal mechanism of DMF sensing. The Zr-doped SnO2 nanofiber field-effect transistors prepared by electrospinning provides a new strategy for exploring DMF sensors with high selectivity and high sensitivity at room temperature.

Mg-doped InSnO nanofiber field-effect transistor for methanol gas detection at room temperature

Research on high-performance gas sensors for detecting toxic and harmful methanol gas is still a very important issue. For gas sensors, it is very important to be able to achieve low concentration detection at room temperature. In this work, we used the electrospinning method to prepare Mg-doped InSnO nanofiber field-effect transistors (FETs) methanol gas sensor. When the Mg element doping concentration is 2.3 mol.%, InSnO nanofiber FET exhibits excellent electrical properties, including higher mobility of 3.17 cm2 V−1 s−1, threshold voltage of 1.51 V, subthreshold swing of 0.42 V/decade, the excellent on/off current ratio is about 108 and the positive bias stress stability of the InSnO nanofiber FET through Mg doping has been greatly improved. In addition, the InSnMgO nanofiber FET gas sensor exhibits acceptable gas selectivity and sensitivity to methanol gas at room temperature. In the methanol gas sensor test at room temperature, when the methanol gas concentration is 60 ppm at room temperature, the response value of the InSnMgO nanofiber FET gas sensor is 81.92; and when the methanol concentration is 5 ppm, the response value is still 1.21. This work provides an effective and novel way to build a gas sensor at room temperature and use it to detect methanol gas at room temperature.

High-Performance IGZO Nanowire-Based Field-Effect Transistors with Random-Network Channels by Electrospun PVP Nanofiber Template Transfer.

A random network of indium–gallium–zinc oxide (IGZO) nanowires was fabricated by electrospun-polyvinylpyrrolidone (PVP)-nanofiber template transfer. Conventional electrospun nanofibers have been extensively studied owing to their flexibility and inherently high surface-to-volume ratio. However, solution-based IGZO nanofibers have critical issues such as poor electrical properties, reliability, and uniformity. Furthermore, high-temperature calcination, which is essential for vaporizing the polymer matrix, hinders their applications for flexible electronics. Therefore, sputter-based IGZO nanowires were obtained in this study using electrospun PVP nanofibers as an etching mask to overcome the limitations of conventional electrospun IGZO nanofibers. Field-effect transistors (FETs) were fabricated using two types of channels, that is, the nanofiber template-transferred IGZO nanowires and electrospun IGZO nanofibers. A comparison of the transmittance, adhesion, electrical properties, reliability, and uniformity of these two channels in operation revealed that the nanofiber template-transferred IGZO nanowire FETs demonstrated higher transmittance, stronger substrate adhesion, superior electrical performance, and operational reliability and uniformity compared to the electrospun IGZO nanofiber FETs. The proposed IGZO nanowires fabricated by PVP nanofiber template transfer are expected to be a promising channel structure that overcomes the limitations of conventional electrospun IGZO nanofibers.

Ultrasensitive room-temperature acetone gas sensors employing green-solvent-processed aligned InNdO nanofiber field-effect transistors

Aligned InNdO nanofiber FETs prepared with green solvents by an electrospinning method for acetone gas detection at room temperature.

High Annealing Stability of InAlZnO Nanofiber Field-Effect Transistors with Improved Morphology by Al Doping.

In2O3 nanofibers usually suffer a high off-current and consequent low on/off current ratio, as well as a large negative threshold voltage (Vth). Furthermore, regarding Zn doped binary-cation In2O3 nanofibers, severe thermal diffusion of Zn elements can result in deteriorated electrical performance when annealed at high temperature. Here, we applied an electrospinning technique to obtain ternary-cation IAZO nanofibers with controllable Vth and chemical stoichiometry. The presence of the Al element in IAZO nanofibers can lead to more superior microstructure with improved uniformity, lower surface defect, and superior metal-oxide-metal lattice at high annealing temperature. Consequently, our Al-doped ternary-cation IAZO devices exhibited an improved on/off current ratio of 107 and a high electron mobility of ∼10 cm2 V-1 s-1. Moreover, the electron mobility can be increased to 30 cm2 V-1 s-1 in our low-voltage operated FETs with high-k AlOx as the dielectric layer, which can be envisioned to exhibit vast implications for high-performance transparent electronics.

Amelioration of interfacial combination and suppression of oxygen vacancies for high performance environmentally friendly electrospun SnYO nanofiber field-effect transistors

Chemical complexation enhances the performance of FETs based on electrospun SnYO nanofibers.

Microwave-assisted calcination of electrospun indium-gallium-zinc oxide nanofibers for high-performance field-effect transistors.

The effects of microwave-assisted calcination of electrospun In–Ga–Zn-O (IGZO) nanofibers intended for electronic devices are unclear. To this end, a systematic study was conducted on the effects of microwave-assisted calcination on the microstructure and optical and mechanical properties of electrospun IGZO nanofibers used in high-performance field-effect transistors (FETs). To clarify the role of microwave annealing (MWA) on the characteristics of the electrospun nanofibers, calcination was carried out using two techniques: MWA and conventional thermal annealing (CTA). The morphological differences between IGZO nanofibers calcined using the two techniques were analyzed by scanning electron microscopy (SEM); the diameter of nanofibers was significantly reduced through MWA as compared to CTA. After calcination, the optical transmittance in the visible region was slightly improved, with the MWA-calcined nanofibers exhibiting a higher transmittance than the CTA-calcined nanofibers. Scratch test results showed that the calcination improved the adhesion strength of the nanofibers to the SiO2 substrate; MWA was more effective in improving the mechanical properties than CTA. Furthermore, the effects of MWA calcination on the electrical properties of FETs fabricated using the electrospun IGZO nanofibers were investigated. The MWA-calcined devices showed better electrical characteristics and reliability than the CTA-calcined devices for IGZO nanofiber FETs.

The role of oxygen in determining the electrical performance of ZnSnO nanofiber field-effect transistors

In recent years, one-dimensional (1D) nanostructures, such as nanotubes, nanowires and nanofibers, have been extensively investigated as potential building blocks in nanoscale devices owing to their excellent physical and chemical properties. In this report, zinc tin oxide (ZnSnO) nanofiber networks (NFNs) were fabricated by electrospinning, and the surface morphologies, crystallinities, grain size distributions, and chemical compositions of the nanofibers annealed in different atmospheres were systematically investigated. To verify the possible applications, field-effect transistors (FETs) based on ZnSnO NFNs/SiO2 were integrated. It is found that the field-effect mobility (µFE) of FETs based on ZnSnO NFNs annealed in oxygen is an order of magnitude higher than those annealed in air. When high-κ ZrOx thin film was employed as gate dielectric, the operating voltage was substantially reduced and a high µFE of 21.58 cm2 V−1 s−1 was achieved for the FETs based on ZnSnO NFNs annealed at 500 °C in oxygen. FETs based on oxygen-annealed ZnSnO NFNs/ZrOx exhibit great potential for applications in low-cost and low-voltage devices.

Highly flexible chemical sensors based on polymer nanofiber field-effect transistors

Electrospun semiconducting polymer nanofibers functionalized with specific container molecules have been used for flexible and high-performance chemical sensors.

Photochemical Activation of Electrospun In2O3 Nanofibers for High-Performance Electronic Devices

Electrospun metal oxide nanofibers have been regarded as promising blocks for large-area, low-cost, and one-dimensional electronic devices. However, the electronic devices based on electrospun nanofibers usually suffer from poor performance and inferior viability. Here, we report an efficient photochemical process using UV light generated by a high-pressure mercury lamp to promote the electrical performance of the nanofiber-based electronic devices. Such UV treatment can lead to strong photochemical activation of electrospun nanofibers, and therefore, a stable adherent nanofiber network and electronic-clean interface were formed. By use of UV treatment, high-performance indium oxide (In2O3) nanofiber based field-effect transistors (FETs) with highly efficient modulation of electrical characteristics have been successfully fabricated. To reduce the operating voltage and further improve the device performance, the In2O3 nanofiber FETs based on solution-processed high-k AlOx dielectrics were integrated and investigated. The as-fabricated In2O3/AlOx FETs exhibit superior electrical performance, including a high mobility of 19.8 cm2 V-1 s-1, a large on/off current ratio of 106, and high stability over time and cycling. The improved performance of the UV-treated FETs was further confirmed by the integration of the electrospun In2O3/AlOx FETs into inverters. This work presents an important advance toward the practical applications of electrospun nanofibers for functional electronic devices.

Flexible organic field-effect transistors based on electrospun conjugated polymer nanofibers with high bending stability

We report on flexible, single electrospun nanofiber field-effect transistors made by a blend of poly(3-decylthiophene) and poly(3-hexylthiophene), assessing for the first time the performances of this class of devices in terms of stability upon repeated tensile bending. Charge-carrier mobilities in the nanofiber-based device are estimated of the order of 10−3cm2/(Vs). Repeated cycles of bending and relaxing are performed, and the evolution of the device current–voltage characteristics is monitored up to 1000 cycles. We find that during bending the mobility is higher than that measured in planar conditions, and that after about 100 bending cycles it rapidly stabilizes. The here observed bending stability suggests a high compatibility of electrospun nanofibers with devices fabricated by roll-to-roll processes, and with bendable or wearable electronics.

P3HT-fiber-based field-effect transistor: Effects of nanostructure and annealing temperature

Poly(3-hexylthiophene) nanofibers were prepared under ambient conditions and applied in organic field-effect transistors (FETs). Top-contact FETs with spin-coated and nanofiber-based layers were fabricated to compare their transport performance. It was found that the nanofiber FET shows a higher performance than the spin-coated one. The effects of annealing on the device performance of the nanofiber FET were also investigated from room temperature to 120 °C. The key performance characteristics of the nanofiber FET, such as carrier mobility and ON/OFF ratio, were improved by low-temperature annealing up to 80 °C. However, they were degraded by high-temperature annealing at 120 °C. The modulation of the surface morphology observed by atomic force microscopy is consistent with the change in device performance. The results of the correlation analysis of the mobility, hysteresis, and OFF current indicate that the change in FET performance is due to the disappearance of nanofiber interspaces and the removal of adsorbed molecules by temperature-controlled annealing.

Single light-emitting polymer nanofiber field-effect transistors

We report on single nanofiber field-effect transistors made by the light-emitting polymer, poly(2-methoxy-5-(2-ethylhexoxy)-1,4-phenylenevinylene). We measure electrical performances comparable to or better than those of thin-film transistors by the same organic semiconductor, due to the molecular alignment induced by electrospinning, such as hole mobility of the order of 10(-3) cm(2) V(-1) s(-1) and on/off current ratios up to 780. In addition, we observe controllable photoluminescence intensity quenching by varying the gate voltage up to -40 V with device operation in the luministor mode. Single light-emitting polymer nanofiber transistors coupling electrical and optical functionalities open the way towards low cost and flexible one-dimensional switches and nanofiber-based light-emitting transistors.

Continuous production of uniform poly(3-hexylthiophene) (P3HT) nanofibers by electrospinning and their electrical properties

Uniform regio-regular poly(3-hexylthiophene) nanofibers and their blend nanofibers with poly(e-caprolactone) have been obtained by electrospinning and their electrical properties in single nanofiber field effect transistors have been compared. The key to the success was restricting the precipitation of P3HT at the nozzle tip, therefore preventing the nozzle from being clogged. The field effect mobility of pure P3HT fibers was 0.017 cm2V−1 s−1 which is acceptable for device fabrication. Blend fibers with PCL also showed field effect behaviour with slightly degraded electrical properties by an order or two.