Download or read book Interface and Morphology Engineering for Polymer and ZnO Thin film Transistors Toward High Mobility and Stability written by 傅榆 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interface Engineering in Organic Field Effect Transistors written by Xuefeng Guo and published by John Wiley & Sons. This book was released on 2023-07-05 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interface Engineering in Organic Field-Effect Transistors Systematic summary of advances in developing effective methodologies of interface engineering in organic field-effect transistors, from models to experimental techniques Interface Engineering in Organic Field-Effect Transistors covers the state of the art in organic field-effect transistors and reviews charge transport at the interfaces, device design concepts, and device fabrication processes, and gives an outlook on the development of future optoelectronic devices. This book starts with an overview of the commonly adopted methods to obtain various semiconductor/semiconductor interfaces and charge transport mechanisms at these heterogeneous interfaces. Then, it covers the modification at the semiconductor/electrode interfaces, through which to tune the work function of electrodes as well as reveal charge injection mechanisms at the interfaces. Charge transport physics at the semiconductor/dielectric interface is discussed in detail. The book describes the remarkable effect of SAM modification on the semiconductor film morphology and thus the electrical performance. In particular, valuable analyses of charge trapping/detrapping engineering at the interface to realize new functions are summarized. Finally, the sensing mechanisms that occur at the semiconductor/environment interfaces of OFETs and the unique detection methods capable of interfacing organic electronics with biology are discussed. Specific sample topics covered in Interface Engineering in Organic Field-Effect Transistors include: Noncovalent modification methods, charge insertion layer at the electrode surface, dielectric surface passivation methods, and covalent modification methods Charge transport mechanism in bulk semiconductors, influence of additives on materials’ nucleation and morphology, solvent additives, and nucleation agents Nanoconfinement effect, enhancing the performance through semiconductor heterojunctions, planar bilayer heterostructure, ambipolar charge-transfer complex, and supramolecular arrangement of heterojunctions Dielectric effect in OFETs, dielectric modification to tune semiconductor morphology, surface energy control, microstructure design, solution shearing, eliminating interfacial traps, and SAM/SiO2 dielectrics A timely resource providing the latest developments in the field and emphasizing new insights for building reliable organic electronic devices, Interface Engineering in Organic Field-Effect Transistors is essential for researchers, scientists, and other interface-related professionals in the fields of organic electronics, nanoelectronics, surface science, solar cells, and sensors.

Download or read book Interface and Morphology Engineering in Solution processed Electronic and Optoelectronic Devices written by Sanjib Das (Electrical engineer) and published by . This book was released on 2015 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this dissertation focuses on interface and morphology engineering in polymer- and small molecule-based organic solar cells. High-performance devices were fabricated, and the device performance was correlated with nanoscale structures using various electrical, spectroscopic and microscopic characterization techniques, providing guidelines for high-efficiency cell design. The second part focuses on perovskite solar cells (PSCs), an emerging photovoltaic technology with skyrocketing rise in power conversion efficiency (PCE) and currently showing comparable PCEs with those of existing thin film photovoltaic technologies such as CIGS and CdTe. Fabrication of large-area PSCs without compromising reproducibility and device PCE requires formation of dense, pinhole-free and highly uniform perovskite thin films over large area, which remains a big challenge as of today. In this work, a scalable process, called ultrasonic spray-coating (USC), was thoroughly optimized to deposit dense and uniform perovskite thin films for high-efficiency PSCs. In order to realize high-performance flexible PSCs, a unique photonic curing technique was demonstrated to achieve highly conductive TiO2 as electron transport layer on flexible substrates. Moreover, the effect of processing conditions on perovskite film growth was evaluated and taken into account to increase PCE to more than 15%. In addition, a series of high-performance organic field-effect transistors (OFETs) were fabricated en route to demonstrate the versatility of the USC process. Several different polymer binders were used to modulate the lateral and vertical phase morphologies in OFETs, significantly improving the device performance. In summary, this research provides guidelines for the design and fabrication of high-performance solution-processed solar cells and field-effect transistors based on organic materials and hybrid perovskites, while presenting a viable route for large-scale fabrication.

Download or read book Transparent Electronics written by Elvira Fortunato and published by . This book was released on with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Synthesis and Structure Property Relationship Study of Polymer Field Effect Transistors written by Ting Lei and published by Springer. This book was released on 2015-01-05 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book summarizes Ting Lei’s PhD study on a series of novel conjugated polymers for field-effect transistors (FETs). Studies contain many aspects of polymer FETs, including backbone design, side-chain engineering, property study, conformation effects and device fabrication. The research results have previously scattered in many important journals and conferences worldwide. The book is likely to be of interest to university researchers, engineers and graduate students in materials sciences and chemistry who wish to learn some principles, strategy, and applications of polymer FETs.

Download or read book High Performance and High Stability Zno Thin Film Transistors written by 吳孟倫 and published by . This book was released on 2008 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ZnO Thin Film Transistors for Cost Efficient Flexible Electronics written by Fábio Fedrizzi Vidor and published by Springer. This book was released on 2017-12-28 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the integration, characterization and analysis of cost-efficient thin-film transistors (TFTs), applying zinc oxide as active semiconductors. The authors discuss soluble gate dielectrics, ZnO precursors, and dispersions containing nanostructures of the material, while different transistor configurations are analyzed with respect to their integration, compatibility, and device performance. Additionally, simple circuits (inverters and ring oscillators) and a complementary design employing (in)organic semiconducting materials are presented and discussed. Readers will benefit from concise information on cost-efficient materials and processes, applied in flexible and transparent electronic technology, such as the use of solution-based materials and dispersion containing nanostructures, as well as discussion of the physical fundamentals responsible for the operation of the thin-film transistors and the non-idealities of the device.

Download or read book Organic Thin Film Transistor Integration written by Flora Li and published by John Wiley & Sons. This book was released on 2011-03-21 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on organic electronics (or plastic electronics) is driven by the need to create systems that are lightweight, unbreakable, and mechanically flexible. With the remarkable improvement in the performance of organic semiconductor materials during the past few decades, organic electronics appeal to innovative, practical, and broad-impact applications requiring large-area coverage, mechanical flexibility, low-temperature processing, and low cost. Thus, organic electronics appeal to a broad range of electronic devices and products including transistors, diodes, sensors, solar cells, lighting, displays, and electronic identification and tracking devices A number of commercial opportunities have been identified for organic thin film transistors (OTFTs), ranging from flexible displays, electronic paper, radio-frequency identification (RFID) tags, smart cards, to low-cost disposable electronic products, and more are continually being invented as the technology matures. The potential applications for "plastic electronics" are huge but several technological hurdles must be overcome. In many of these applications, transistor serves as a fundamental building block to implement the necessary electronic functionality. Hence, research in organic thin film transistors (OTFTs) or organic field effect transistors (OFETs) is eminently pertinent to the development and realization of organic electronics. This book presents a comprehensive investigation of the production and application of a variety of polymer based transistor devices and circuits. It begins with a detailed overview of Organic Thin Film Transistors (OTFTs) and discusses the various possible fabrication methods reported so far. This is followed by two major sections on the choice, optimization and implementation of the gate dielectric material to be used. Details of the effects of processing on the efficiency of the contacts are then provided. The book concludes with a chapter on the integration of such devices to produce a variety of OTFT based circuits and systems. The key objective is to examine strategies to exploit existing materials and techniques to advance OTFT technology in device performance, device manufacture, and device integration. Finally, the collective knowledge from these investigations facilitates the integration of OTFTs into organic circuits, which is expected to contribute to the development of new generation of all-organic displays for communication devices and other pertinent applications. Overall, a major outcome of this work is that it provides an economical means for organic transistor and circuit integration, by enabling the use of a well-established PECVD infrastructure, while not compromising the performance of electronics. The techniques established here are not limited to use in OTFTs only; the organic semiconductor and SiNx combination can be used in other device structures (e.g., sensors, diodes, photovoltaics). Furthermore, the approach and strategy used for interface optimization can be extended to the development of other materials systems.

Download or read book Studies of Polymer Field effect Transistors written by Felix Sunjoo Kim and published by . This book was released on 2012 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: The era of plastic electronics is rapidly emerging due to the increasing development and application of low-cost, printable, shape-conforming, and large-area devices, such as organic field-effect transistors (OFETs) and circuits, organic solar cells, and organic light-emitting devices. Deepening our understanding of charge-carrier dynamics in polymer semiconductors is critical to the future advances in organic electronics. This dissertation focuses on studies of OFETs and aims to better understand the charge transport properties of polymer semiconductors and factors that influence the performance of OFETs. Case studies of structure-morphology-property relationships in unipolar p- and n-channel polymer OFETs as well as ambipolar OFETs reveal that variations in molecular structure and processing affect electronic energy levels, solid-state morphology and crystallinity, and thus the magnitude and polarity of charge carriers. The studies resulted in achievement of high-performance OFETs with high charge-carrier mobility of up to 0.3 cm2/Vs. The morphology and electronic energy levels are also related to ambient stability and durability of polymer OFETs through kinetics and thermodynamics of interaction between the semiconductor and extrinsic molecules in ambient air. Air-stable ambipolar OFETs were realized by utilizing unipolar p- and n-type polymer semiconductors as the active channel elements. Complementary digital logic circuits such as inverters and NAND- and NOR-gates, were also demonstrated using the unipolar and ambipolar OFETs. Device engineering studies show that electron mobility and electrical stability of n-channel polymer OFETs can be significantly enhanced by inserting a low-dielectric-constant polymer dielectric buffer layer at the semiconductor/dielectric interface. Electron mobility was found to increase exponentially with decreasing dielectric constant of the buffer layer. Finally, poly(3-butylthiophene)-nanowire/polystyrene nanocomposites were also investigated as a means of controlling the solid-state morphology of active thin films in OFETs. High dc conductivity and high hole mobility were obtained throughout a wide range of the nanowire compositions (2-100 wt%) due in part to the very low percolation threshold (0.5 wt%).

Download or read book Amorphous Silicon Thin Film Transistors written by Zoubeida Hafdi and published by Springer Nature. This book was released on 2023-03-03 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the basic elements that readers need to know about amorphous silicon material and a-Si:H TFTs. It includes the main principles of the transistors operation, modeling and applications. Fundamentals about transport mechanisms in a-Si:H TFTs and the associated electronic properties are introduced and extended to design examples and strategies to build reliable, large-area, performance optimized circuits. The book also reviews the effect of the amorphous silicon nature and how it impacts the transistors properties and their relevant applications. Fundamentals are made as simple as possible to be easily grasped as they cover everything expected to be important for an easy understanding of the introduced concepts. The author’s approach is geared toward undergraduate and graduate students, but the content is also appropriate for circuit simulator developers, integrated circuit designers and manufacturers, as well as everyone engaged in work on large area integrated circuit technologies and photovoltaics.

Download or read book An Investigation of the Performance and Stability of Zinc Oxide Thin film Transistors and the Role of High k Dielectrics written by Ngwashi Divine Khan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent oxide semiconducting films have continued to receive considerable attention, from a fundamental and application-based point of view, primarily because of their useful fundamental properties. Of particular interest is zinc oxide (ZnO), an n-type semiconductor that exhibits excellent optical, electrical, catalytic and gas-sensing properties, and has many applications in various fields. In this work, thin film transistor (TFT) arrays based on ZnO have been prepared by reactive radio frequency (RF) magnetron sputtering. Prior to the TFT fabrication, ZnO layers were sputtered on to glass and silicon substrates, and the deposition parameters optimised for electrical resistivities suitable for TFT applications. The sputtering process was carried out at room temperature with no intentional heating. The aim of this work is to prepare ZnO thin films with stable semiconducting electrical properties to be used as the active channel in TFTs; and to understand the role of intrinsic point defects in device performance and stability. The effect of oxygen (O2) adsorption on TFT device characteristics is also investigated. The structural quality of the material (defect type and concentration), electrical and optical properties (transmission/absorption) of semiconductor materials are usually closely correlated. Using the Vienna ab-initio simulation package (VASP), it is predicted that O2 adsorption may influence film transport properties only within a few atomic layers beneath the adsorption site. These findings were exploited to deposit thin films that are relatively stable in atmospheric ambient with improved TFT applications. TFTs incorporating the optimised layer were fabricated and demonstrated very impressive performance metrics, with effective channel mobilities as high as 30 cm2/V-1s-1, on-off current ratios of 107 and sub-threshold slopes of 0.9? 3.2 V/dec. These were found to be dependent on film thickness (~15? 60 nm) and the underlying dielectric (silicon dioxide (SiO2), gadolinium oxide (Gd2O3), yttrium oxide (Y2O3) and hafnium oxide (HfO2)). In this work, prior to sputtering the ZnO layer (using a ZnO target of 99.999 % purity), the sputtering chamber was evacuated to a base pressure ~4 x 10-6 Torr. Oxygen (O2) and argon (Ar) gas (with O2/Ar ratio of varying proportions) were then pumped into the chamber and the deposition process optimised by varying the RF power between 25 and 500 W and the O2/Ar ratio between 0.010 to 0.375. A two-level factorial design technique was implemented to test specific parameter combinations (i.e. RF power and O2/Ar ratio) and then statistical analysis was utilised to map out the responses. The ZnO films were sputtered on glass and silicon substrates for transparency and resistivity measurements, and TFT fabrication respectively. For TFT device fabrication, ZnO films were deposited onto thermally-grown silicon dioxide (SiO2) or a high-k dielectric layer (HfO2, Gd2O3 and Y2O3) deposited by a metal-organic chemical deposition (MOCVD) process. Also, by using ab initio simulation as implemented in the?Vienna ab initio simulation package (VASP)?, the role of oxygen adsorption on the electrical stability of ZnO thin film is also investigated. The results indicate that O2 adsorption on ZnO layers could modify both the electronic density of states in the vicinity of the Fermi level and the band gap of the film. This study is complemented by studying the effects of low temperature annealing in air on the properties of ZnO films. It is speculated that O2 adsorption/desorption at low temperatures (150? 350 0C) induces variations in the electrical resistance, band gap and Urbach energy of the film, consistent with the trends predicted from DFT results.

Download or read book Organic Thin Film Transistor Applications written by Brajesh Kumar Kaushik and published by CRC Press. This book was released on 2016-09-15 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Text provides information about advanced OTFT (Organic thin film transistor) structures, their modeling and extraction of performance parameters, materials of individual layers, their molecular structures, basics of pi-conjugated semiconducting materials and their properties, OTFT charge transport phenomena and fabrication techniques. It includes applications of OTFTs such as single and dual gate OTFT based inverter circuits along with bootstrap techniques, SRAM cell designs based on different material and circuit configurations, light emitting diodes (LEDs). Besides this, application of dual gate OTFT in the logic gate, shift register, Flip-Flop, counter circuits will be included as well.

Download or read book Short Channel Organic Thin Film Transistors written by Tarek Zaki and published by Springer. This book was released on 2015-05-27 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work takes advantage of high-resolution silicon stencil masks to build air-stable complementary OTFTs using a low-temperature fabrication process. Plastic electronics based on organic thin-film transistors (OTFTs) pave the way for cheap, flexible and large-area products. Over the past few years, OTFTs have undergone remarkable advances in terms of reliability, performance and scale of integration. Many factors contribute to the allure of this technology; the masks exhibit excellent stiffness and stability, thus allowing OTFTs with submicrometer channel lengths and superb device uniformity to be patterned. Furthermore, the OTFTs employ an ultra-thin gate dielectric that provides a sufficiently high capacitance to enable the transistors to operate at voltages as low as 3 V. The critical challenges in this development are the subtle mechanisms that govern the properties of aggressively scaled OTFTs. These mechanisms, dictated by device physics, are well described and implemented into circuit-design tools to ensure adequate simulation accuracy.

Download or read book Solution Processed Organic Semiconductor Thin film Transistors for Flexible Electronics written by Zihong Liu and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic or carbon electronics has been a fast-growing field in recent years covering a broad range from nanoelectronic devices to macroelectronic systems. Besides the single-graphene or single-carbon nanotube transistor toward extending the scaling limit of traditional silicon metal-oxide-semiconductor field-effect transistor (MOSFET), organic semiconductor based thin-film transistors have been actively investigated due to their promise in large-area electronics fabricated on flexible substrates using low-cost unconventional means, such as low/room-temperature printing and roll-to-roll processing. This dissertation focuses on the study of device physics, device modeling, fabrication technology, and interface engineering for solution-processed organic field-effect transistors (SPOFET) for flexible electronics applications. There are primarily four parts of contributions originated from this dissertation work. The first part introduces the design and demonstration of high-performance, low-voltage flexible SPOFETs fabricated on plastic substrates with a carrier mobility over 0.2 cm2/Vs, a turn-on voltage of near 0 V, and a record low subthreshold slope of ~80 mV/dec in ambient conditions. These exceptional characteristics are achieved by novel device architecture design, 3-D statistical modeling for solution-shearing process optimization, and phenyl-terminated self-assembled monolayer (SAM) based interface engineering. In the second part, SAM relevant physical effects and chemistry effects at the organic semiconductor-dielectric interface are systematically investigated. Through careful selection of a group of phenyl-terminated SAMs, we elucidate how the performance and reliability of organic transistors are controlled by the critical semiconductor-dielectric interfacial SAMs. In addition, we briefly introduce a spin-coating process for depositing high-quality phenyl-terminated SAMs for organic electronics applications. The third part focuses on the device physics and device modeling of organic transistors. In this dissertation work, we have proposed and developed a universal physical model for organic transistors by incorporating both the charge injection effects and charge transport properties, and successfully applied it to resolve many elusive physical phenomena observed so far, such as the peculiar mobility scaling behavior with respect to the channel length, the contact resistance effect, and the mysterious surface potential profiles of organic transistors which have been experimentally probed yet poorly understood. Of particular importance is that we discover an overshoot region in the mobility scaling behavior and identified the existence of a critical channel length for the peak field-effect mobility. In the last part, we investigate novel contact engineering for organic transistors toward lowering charge injection barrier and reducing the interfacial disorder width or localization states. We have explored and demonstrated Fermi-level depinning at the metal-organic interface for low-resistance Ohmic contacts by inserting an ultrathin interfacial Si3N4 insulator in between. The contact behavior is successfully tuned from rectifying to quasi-Ohmic and to tunneling by varying the Si3N4 thickness within 0-6 nm. Detailed physical mechanisms of Fermi-level pinning/depinning responsible for the metal-organic semiconductor contact behavior are clarified based on a proposed lumped-dipole model.

Download or read book Proceedings of the Second Symposium on Thin Film Transistor Technologies written by Yue Kuo and published by The Electrochemical Society. This book was released on 1995 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Enhanced Charge Transport in Polymer Thin film Transistors Through Structural and Morphological Optimization written by Brandon Smith and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors offer the potential for low cost, large area, and flexible electronic devices. However, the lower performance of organic materials relative to silicon, germanium, and other inorganic components has prevented widespread implementation. Correspondingly, the overarching goals of the work outlined in this dissertation focus on exploring the fundamental properties and intermolecular interactions of conjugated polymers and utilizing the findings to develop routes for improving thin-film transistor performance. Charge transport in organic active layers depends largely on the intrinsic carrier mobility of the semiconductor, the morphology achieved during processing and fabrication, as well as the effectiveness of the post-processing techniques. In this work, we investigate the influence of each and will show how appropriately tuning polymorphism, copolymerization between strong and weakly crystallizing moieties, and fluorine substitution on delocalized cores significantly enhance transistor characteristics. Crystalline organic molecules often exhibit the ability to assemble into multiple crystal structures depending on the processing conditions. Exploiting this polymorphism to optimize molecular orbital overlap between adjacent molecules in the unit lattice is a viable method for improving charge transport within the material. We have employed grazing-incident X-ray diffraction to demonstrate the formation of tighter stacking poly(3-hexylthiophene-2,5-diyl) polymorphs in films spin coated from ferrocene-containing solutions. As a result, the addition of ferrocene to casting solutions yields thin-film transistors which exhibit approximately three times higher source-drain currents and charge mobilities than neat polymer devices. Nevertheless, thorough analysis of the active layer reveals that all ferrocene is removed during the spin coating process, which may be an essential factor to achieve good mobilities. Such insights gleaned from ferrocene/poly(3-hexylthiophene) mixtures can serve as a template for selection and optimization of other small molecule/polymer systems with greater baseline charge mobilities. Block copolymerization provides yet another avenue for altering the crystal packing behavior and morphology of polymer semiconductors. Our work reveals that covalently coupling a weakly crystalline acceptor polymer with excellent electron mobility to a strongly crystallizing donor unit can induce ordering in the less crystalline block. Grazing-incidence X-ray scattering results confirm that shorter interchain spacing distances are obtained in poly(3-hexylthiophene)-b-poly(fluorene-dithiophene-benzothiadiazole) copolymers compared with neat poly(fluorene-dithiophene-benzothiadiazole) films. An enhancement in the ordering of the acceptor moiety was also observed both in neat homopolymer and copolymer samples after thermal annealing at 195 C. Consequently, the electron mobility of the block copolymer, measured in thin-film transistors with aluminum contacts, surpassed that of either homopolymer and peaked at annealing temperatures between 195 210 C. Several recent reports have surfaced in the literature in which fluorinated analogues of various donor/acceptor copolymers consistently surpass their non-fluorinated counterparts in terms of performance. Prior studies have speculated as to the origin of this fluorine effect, but concrete evidence has not been forthcoming. Using a benzodithiophene and benzotriazole copolymer series consisting of fluorinated, partially-fluorinated, and non-fluorinated analogues, we confirm that the addition of fluorine substituents beneficially impacts charge transport in polymer semiconductors. Transistor measurements demonstrated a 5x rise in carrier mobilities with the degree of fluorination of the backbone. Furthermore, X-ray diffraction data indicates progressively closer packing between the conjugated cores and an overall greater amount of crystallinity in the fluorinated materials. It is likely that attractive interactions between the electron-rich donor and fluorinated electron-deficient acceptor units induce very tightly stacking crystallites, which reduce the energetic barrier for charge hopping. In addition, a change in crystallite orientation was observed from primarily edge-on without fluorine substituents to mostly face-on with dual fluorine groups. We also introduce a promising post-processing technique adapted from existing zone purification and recrystallization methods. Zone annealing and zone refining are proposed for imparting directionality to the crystallization process, thereby increasing the size of crystallites and uninterrupted conjugation lengths within polymer films. A custom nichrome wire-based zone heating apparatus developed for zone refining thin films is described, and preliminary results with poly(3-hexylthiophene) are presented. A comparison with the UV-Vis absorbance of films annealed statically on a hot plate suggests that similar conjugation lengths can be achieved in approximately a sixth of the time with zone refining. Further optimization and investigatory studies are required before the procedure can be successfully extended to transistor samples, but zone crystallization appears to be a highly compatible post-processing approach for large scale manufacturing. The final portion of this work was dedicated to the development of potential integration venues for organic devices. Applications which take full advantage of the unique properties of polymer semiconductors will be needed as organic electronics begin the arduous transition into the commercial sphere. As such, neutron and X-ray detection systems represent two categories where very large area and flexibility would be invaluable. We therefore explore the feasibility of sensitizing conjugated materials towards either neutrons or X-rays through the incorporation of elements possessing excellent neutron capture or X-ray absorption properties. The projected mechanisms and challenges associated with direct radiation detection are discussed, and the results obtained from numerous screening experiments, conducted to determine which compounds maintain acceptable performance in transistors, are included. Based on these trials, boron nitride, 10B-enriched boric acid, and ruthenocene blended with poly(3-hexylthiophene) at extraordinarily high loadings were identified for further scrutiny and eventual response testing with an X-ray or neutron source. In summary, the objectives set forth for this work have been successfully realized. We examined the impact of several parameters governing charge transport in organic semiconductors, and based on our conclusions, we have identified three approaches for substantially augmenting the performance of polymer field-effect transistors. We have also considered a useful post-process treatment for large scale device fabrication and illustrated the benefits and potential for adapting conjugated materials for novel detection applications. The contributions of the research efforts expounded within this dissertation have far reaching implications yet represent only a small part of the general advance of the organic semiconductor field. Significant progress is being made on many critical fronts, and provided the allure of light weight, completely conformable electronics remains strong, we expect to continue witnessing the steady emergence of ever more numerous devices and gadgets based on organic transistors and diodes.

Download or read book Development of Indium Gallium Zinc Oxide Thin Film Transistors on a Softening Shape Memory Polymer for Implantable Neural Interfaces Devices written by Ovidio Rodriguez Lopez and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The continuous improvement in electronic active devices has led to several innovations in semiconductor materials, novel deposition methods, and improved microfabrication techniques. In the same way, the implementation of thin-film technology has revolutionized the semiconductor industry. For instance, the field of flexible electronics has utilized novel thin-film electronics components for the fabrication flexible displays, radio frequency identification (RF-ID) tags, and solar cells. Moreover, flexible electronics have sparked a great interest in the field of bioelectronics, for the fabrication of high-spatial-resolution implantable devices for neural interfaces. This incorporation of thin-film technology can potentially enable stimulation and recording the nervous system activity by utilizing novel, minimally invasive, conformal devices. To achieve this, flexible electronics circuits must possess high performance, reliability, and stability, as well as be resilient to mechanical stress and human body conditions, are some of the requirements that flexible electronics must meet for the realization of these devices. Furthermore, the choice of substrates is also critical since it directly affects final properties of the active devices. Substrates, which are mechanically and biologically compliant, are preferred. For this reason, novel, softening materials like thiol-ene polymers are considered in this research. This work centers on the development of Indium-Gallium-Zinc-Oxide (IGZO) thin-film transistors (TFT) using the thiol-ene softening polymer as substrate. Functional IGZO-TFTs were fabricated on top of 50 μm of a thiol-ene/acrylate shape memory polymer (SMP) and electrically characterized. Hafnium oxide (HfO2) deposited at 100°C by atomic layer deposition was used as gate dielectric, and gold (Au) as contacts. The devices were exposed to oxygen, vacuum and forming gas (FG) environments at 250°C to analyze the effects of these atmospheres on the IGZO-TFTs. Improvement in the electrical performance was noticed after the exposure to FG with a significant change in mobility from 0.01 to 30 cm2 V-1s-1, and a reduction in the threshold voltage shift (∆Vth), which it is translated into an increase on stability. Vacuum and oxygen effects were, also analyzed and compared. Furthermore, a time-dependent dielectric breakdown (TDDB) analysis was performed to define the lifetime of the transistors, where a prediction of 10 years at an operational range below 5 V was obtained. Additionally, the TFTs were encapsulated with 5 μm of SMP and exposed to simulated in vivo conditions. Up to 104 bending cycles were performed to the IGZO-TFTs with a bending radius of 5 mm and then, soaked into PBS solution at 37°C for one week to determine the resilience and reliability of the devices. The encapsulated IGZO-TFTs survived to the PBS environment and demonstrated resilience to mechanical deformation with small changes in the electronic properties. The results provided in this research contribute to the development of complex circuitry based on thin-film devices using mechanically adaptive polymers as a flexible substrate and enable the production of multichannel implantable bioelectronics devices.