Дисертації з теми "Organic Field Effect TransistorsCompared"
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Chua, L. L. "Organic field-effect transistors." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597679.
Повний текст джерелаGünther, Alrun Aline. "Vertical Organic Field-Effect Transistors." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-207731.
Повний текст джерелаThis work represents a comprehensive study of the so-called vertical organic field-effect transistor (VOFET), a novel transistor geometry originating from the fast-growing field of organic electronics. This device has already demonstrated its potential to overcome one of the fundamental limitations met in conventional organic transistor architectures (OFETs): In the VOFET, it is possible to reduce the channel length and thus increase On-state current and switching frequency without using expensive and complex structuring methods. Yet the VOFET's operational principles are presently not understood in full detail. By simulating the expected device behaviour and correlating it with experimental findings, a basic understanding of the charge transport in VOFETs is established and this knowledge is subsequently applied in order to manipulate certain parameters and materials in the VOFET. In particular, it is found that the morphology, and thus the deposition parameters, of the organic semiconductor play an important role, both for a successful VOFET fabrication and for the charge transport in the finished device. Furthermore, it is shown that VOFETs, just like their conventional counterparts, are greatly improved by the application of contact doping. This result, in turn, is used to demonstrate that the VOFET essentially works in almost exactly the same way as a conventional OFET, with only minor changes due to the altered contact arrangement. Working from this realisation, a vertical organic transistor is developed which operates in the inversion regime, thus closing the gap to conventional MOSFET technology and providing a truly promising candidate for high-performance organic transistors as the building blocks for advanced, flexible electronics applications
Mohammad, Ahmed Fareed. "Polyelectrolyte based organic field effect transistors." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-96237.
Повний текст джерелаRitjareonwattu, Supachai. "Ion sensitive organic field effect transistors." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/3292/.
Повний текст джерелаLiu, Shiyi. "Understanding Doped Organic Field-Effect Transistors." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1574127009556301.
Повний текст джерелаWolanin, Piotr Jacek. "Functional organic nanomaterials for field-effect transistors." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723471.
Повний текст джерелаTakshi, Arash. "Organic metal-semiconductor field-effect transistor (OMESFET)." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31531.
Повний текст джерелаApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Cheng, X. "Organic field-effect transistors via inkjet printing." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597572.
Повний текст джерелаArthur, Joshua N. "Hygroscopic insulator organic field effect transistor sensors." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/232689/1/Joshua_Arthur_Thesis.pdf.
Повний текст джерелаChiu, Yu-Jui. "Wet Organic Field Effect Transistor as DNA sensor." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11761.
Повний текст джерелаLabel-free detection of DNA has been successfully demonstrated on field effect transistor (FET) based devices. Since conducting organic materials was discovered and have attracted more and more research efforts by their profound advantages, this work will focus on utilizing an organic field effect transistor (OFET) as DNA sensor.
An OFET constructed with a transporting fluidic channel, WetOFET, forms a fluid-polymer (active layer) interface where the probe DNA can be introduced. DNA hybridization and non-hybridization after injecting target DNA and non-target DNA were monitored by transistor characteristics. The Hysteresis area of transfer curve increased after DNA hybridization which may be caused by the increasing electrostatic screening induced by the increasing negative charge from target DNA. The different morphology of coating surface could also influence the OFET response.
Sou, Antony. "Principles of organic field effect transistor circuit design." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708548.
Повний текст джерелаZhang, Xiaohong. "Device engineering of organic field-effect transistors toward complementary circuits." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28150.
Повний текст джерелаCommittee Chair: Kippelen, Bernard; Committee Member: Brand, Oliver; Committee Member: Graham, Samuel; Committee Member: Rohatgi, Ajeet; Committee Member: Shen, Shyh-Chiang.
Toader, Iulia Genoveva. "Electrical and Morphological Characterisation of Organic Field-Effect Transistors." Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-100403.
Повний текст джерелаYusoff, Rashid Bin Mohd. "Magnetic field effect in organic semiconducting materials and devices." reponame:Repositório Institucional da UFPR, 2011. http://hdl.handle.net/1884/26437.
Повний текст джерелаMarjanovic, Nenad. "Photoresponsive organic field-effect transistors (photOFETs) photodoping in OFETs." Saarbrücken VDM Verlag Dr. Müller, 2006. http://d-nb.info/989371336/04.
Повний текст джерелаJarrett, C. P. "Charge transport in solution-processable organic field-effect transistors." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605062.
Повний текст джерелаLeonardi, Francesca <1986>. "Self-Assembled Monolayers (SAMs) in Organic Field-Effect Transistors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6461/.
Повний текст джерелаNasrallah, Iyad. "Investigating charge trapping effects in organic field-effect transistors." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709425.
Повний текст джерелаRyu, Kyungbum. "Characterization of organic field effect transistors for OLED displays." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33853.
Повний текст джерелаIncludes bibliographical references (p. 49-51).
This thesis explores the characterization of OFETs that will aid the circuit design of OLED pixel drivers. The contact resistance, flat band voltage, and mobility are extracted from top contact and bottom contact transistors with current-voltage (I-V) and low frequency capacitance-voltage (C-V) measurements. Extraction of contact resistance is found to be crucial in characterization of bottom-contact transistors as it obscures mobility extraction. An unambiguous method of extracting flat band voltage is explored and mobility is extracted with minimal assumptions by separation of charge and mobility from C-V measurements. Mobility is found to increase with gate voltage differing significantly from mobility dependence in crystal silicon MOSFETs.
by Kyungbum Ryu.
S.M.
Lu, Kexin. "Organic semiconductors for self-assembled monolayer field effect transistors." Thesis, University of Manchester, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559330.
Повний текст джерелаVaklev, Nikolay Lyubomirov. "Organic field-effect transistors with printed dielectrics and semiconductors." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/44879.
Повний текст джерелаPRENTICE, DAVID CHARLES. "SIMULATION OF PENTACENE ORGANIC METAL-OXIDE FIELD EFFECT TRANSISTORS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060200543.
Повний текст джерелаHague, Lee. "The vapour sensing capabilities of organic field-effect transistors." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3196/.
Повний текст джерелаZhang, Qiaoming. "Electrolyte-gated organic field-effect transistors based on organic semiconductor: insulating polymer blends." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667288.
Повний текст джерелаThe present Doctoral Thesis is focused on the fabrication, optimization, characterization and application of organic semiconductors:insulating polymer blends for electrolyte-gated organic field-effect transistors (EGOFETs), which are considered a promising sensing platform in the field of bioelectronics due to their ability to operate in common electrolyte media. Up to date, although several research works have already demonstrated the high potential of using EGOFETs as sensing platform, some unsolved problems (i.e. low carrier mobility, slow response time and fast degradation) are actually hindering their practical application. Within this context, the thesis is divided into three main parts, from EGOFET devices fabrication to their applications. The first part of the thesis aims to obtain robust and efficient EGOFETs device based on two overlooked strategies: (i) the exploitation of blends composed by an insulating polymer and an organic semiconductor (OSC) and (ii) the use of a solution-shearing technique, such as bar-assisted meniscus shearing (BAMS), to deposit the OSC:PS blend. In this part (Chapter 2), four OSCs, including three small molecules and one polymer, were selected as active materials for the fabrication of EGOFETs. The four OSC:polymer blends EGOFET devices have been systematically studied by evaluating and comparing their transfer and output characteristics, potentiometric sensitivity, switching speed and their electrical stability properties recorded in MilliQ water and a NaCl solution as electrolyte media. In addition, the second part of the thesis (Chapter 3) is devoted to the development of a mercury ions sensor based on an EGOFETs by systematically exposing the blend films to a mercury ions aqueous solutions. In this case, a gradual positive threshold voltage shift of the electrical characteristics was observed, which was selected as the detection parameter towards mercury ions. Furthermore, Kelvin probe force microscopy and electrochemical impedance spectroscopy tests were carried out to explore the mechanism of the mercury response, which was demonstrated to be related to the redox reaction between Hg2+ ions and the semiconductor surface. Finally, the third part of the thesis (Chapter 4) is focused on the fabrication of a novel EGOFET device, namely a hydrogel-gated organic field-effect transistor (HYGOFET). A high performance HYGOFET device was achieved by replacing the liquid electrolyte with a water-based hydrogel to serve as dielectric layer. Furthermore, the HYGOFET exhibits an excellent response to pressure stimuli due to the alignment of water dipoles within the OSC layer. The device can thus be envisioned as proof of concept device which can be find applications in the field of textile electronic skin.
Roberson, Luke Bennett. "Understanding organic thin film properties for microelectronic organic field-effect transistors and solar cells." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11072005-111532/.
Повний текст джерелаMohan Srinivasarao, Committee Member ; David Collard, Committee Member ; Uwe Bunz, Committee Member ; Art Janata, Committee Member ; Marcus Weck, Committee Member ; Laren Tolbert, Committee Chair.
Campos, García Antonio. "Influence of organic semiconductors morphology, structure and processability on organic field-effect transistors performance." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666648.
Повний текст джерелаIn this thesis we have studied how the processing of organic semiconductors can affect their morphology and crystal structure. p-Type and n-type organic semiconductors have been employed as active layers in Organic Field-Effect Transistors (OFETs). More in detail, we have performed studies with different organic semiconductors and fabricated transistors based on them by solution (drop casting and bar-assisted meniscus shearing) and by evaporation. The purpose of the work carried out has been elucidating the correlation of the molecular structure, crystal packing and thin film morphology with the electrical properties of the organic semiconductor. Further, aiming at enhancing the performance and stability of the devices, the organic semiconductors used in this thesis were blended with polymer binders. In addition, the effect of the polymer binder has been studied in detail by comparing OFETs based on thin-films of the pristine semiconductor with OFETs based on thin-films of the semiconductor blended with polymers. Finally, spray printing has been explored as technique for depositing organic contacts based on the organic metal tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) and also for forming single crystals of organic semiconductors.
Del, Pozo León Freddy G. "Coating engineering of composite materials for organic field-effect transistors." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284993.
Повний текст джерелаThis thesis describes the development of a technology to deposit thin films of insulating polymers and composite materials for applications in organic field-effect transistors (OFETs). Composite materials are comprised of a semiconductor and an insulator. The insulator is the binder and the semiconductor the active material. The active materials are either polymers or small molecules. Binders are styrenes, methacrylates or combinations of both. In order to first demonstrate the capabilities of the technology developed, namely Bar Assisted Meniscus Sheering (BAMs), thin films of polystyrene on Si/SiOx were deposited, typical thicknesses in the range of 50 to 80 nm were found, also RMS values in the range of 0.5 – 0.6 nm were found as well, and confirms very smooth films with tentative application as dielectrics. Poly-(3-hexylthiophene) (P3HT) is widely used is organic field-effect transistors. Composite materials comprised of P3HT and polystyrene were tested. OFETs fabricated based on composites which only use a 10 % of the active material exhibited a mobility of 0.1 cm2V-1s-1 such value match the maximum mobility value reported in literature to-date for pure P3HT. It is important to highlight that all OFETs fabricated by BAMS using based on the composites have threshold voltages around zero volts despite the fact that all fabrication and characterization were carried out in air. Polymeric semiconductors plays a very important role inside organic semiconductors, due to their advantage the processability. On the other hand, small-molecules lacks processability but in general possess high mobility than polymeric semiconductors. So, composite materials were devised to add processability to small-molecules, but trying to maintain high mobility. TTF derivatives, dibenzo - tetharthiafulvalene (DB-TTF), dithiophene - tetrathiafulvalene (DT-TTF) and bis(ethylenethio) – tetrathiafulvalene (BET-TTF) were the three small-molecules investigated. First, thermally evaporated films of pure DB-TTF and BET-TTF were investigated and their stability in air assessed, found that both are extremely unstable under the presence of oxygen and water even at ppm levels. The inclusion of BAMs have been proven effective in order to produce OFETs based on composites -- insulator binder and TTF-derivatives. First, poly−(−μετηψλ styrene) PAMS, and DB-TTF composites were investigated. OFETs fabricated shows stability in air and text-book like output and transfer characteristics, all with acceptable mobilities in the range of 10-3 cm2V-1s-1. Also OFETs based on isotactic polystyrene and DB-TTF were investigated reporting mobilities in the range of 10-2 cm2V-1s-1. Further, an screening of compositions for composites were carried out, varying blend ratios and the molecular weight of the polystyrene. The screening was carried out using bottom and top contact devices. The screening revealed that the best performing blend is DB-TTF and polystyrene for GPC 3000 (PS3000) in a ratio 1:2. After an in-depth study have been conducted found average mobility for such blend in the range of 10-1 cm2V-1s-1 and threshold voltages close to zero volts were also found, however is worth to highlight that mobility values as high as 0.7 cm2V-1s-1 were also found. Temperature measurements have been carried out and revealed that the charge transport found for these devices (DB-TTF:PS3000 1:2) point towards a temperature independent mobility, that to the best of our knowledge to-date is the first organic solution processed semiconductor that exhibits such behavior. Also when devices construct inverters gains as high as 300 were found, which also to-date and to the best of our knowledge is the highest gain value for organic based inverters.
Hauff, Elizabeth von. "Field effect investigations of charge carrier transport in organic semiconductors." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=981450210.
Повний текст джерелаBarker, Paul Simon. "Gas sensing using an organic/silicon hybrid field-effect transistor." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5166/.
Повний текст джерелаGenerali, Gianluca <1977>. "Organic heterostructure approach for multifunctional light-emitting field-effect transistors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3568/.
Повний текст джерелаSinno, Hiam. "Polyelectrolyte-Gated Organic Field Effect Transistors – Printing and Electrical Stability." Doctoral thesis, Linköpings universitet, Fysik och elektroteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98439.
Повний текст джерелаVerma, Vishash. "Improved Slope Estimation in Organic Field-Effect Transistor Mobility Estimation." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1618703169092189.
Повний текст джерелаLi, Xiang. "Organic Molecules for Field Effect Transistors and Redox Flow Batteries." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1601396172154889.
Повний текст джерелаSahin, Tiras Kevser. "Magnetic field effect and other spectroscopies of organic semiconductor and hybrid organic-inorganic perovskite devices." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6495.
Повний текст джерелаKalb, Wolfgang L. "Trap states in organic field-effect transistors: quantification, identification and elimination /." Zürich : ETH, 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18324.
Повний текст джерелаTemiño, Gutiérrez Inés. "Solution-processed organic field-effect transistors: from fundamental aspects to applications." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/669373.
Повний текст джерелаIn this thesis we have studied several aspects related to organic field-effect transistors (OFETs) printed from solution, including their fabrication, their electrical characterisation, and further applications, especially in the field of physical sensing. Blends of different p‑type small molecule organic semiconductors (OSCs) and insulating polymer binders have been employed in this research work. For the deposition of such blends as active layers for OFETs a scalable solution processing technique has been exploited, namely bar‑assisted meniscus shearing (BAMS). The main purpose of the work carried out has been understanding the influence of the fabrication parameters of choice on the morphological and structural features of the resulting active layer and, thus, their impact on the electrical performance of the final devices. A detailed nanoscale study of OSC:insulating polymer thin films has been conducted, elucidating the vertical stratification of both components and its effect on the devices stability and performance. Further, aiming at improving the electrical characteristics of devices exhibiting high contact resistance values, different doping methodologies have been explored. In addition, the morphology-performance relationship has been studied for flexible OFET devices subjected to mechanical strain. Finally, OFETs exhibiting high sensitivity to X-ray radiation have been fabricated by optimising the processing parameters, rationalising how the morphological and transport properties of the active layer determine the sensing capability of such devices.
Gay, Nicolas [Verfasser]. "Analog Circuit Design based on Organic Field-Effect Transistors / Nicolas Gay." Aachen : Shaker, 2007. http://d-nb.info/1166509966/34.
Повний текст джерелаChang, Wendi. "Characterization of Local field effect in organic film using pressure technique." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82374.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 63-65).
This thesis proposes and demonstrates a pressure probing technique for studying the effects of local dielectric changes on the excitonic energy levels in amorphous organic thin films for optoelectronic device applications. Compression of organic films causes a decrease in intermolecular spacing and, through solvation effects, lowers the exciton transition energy. A series of steady-state photoluminescence (PL) measurements performed on doped organic thin films demonstrated the applicability of pressure probing in measuring solvation effects, and fitted to solvation theory. Since a pressure probing technique eliminates composition differences and sample-to-sample variability, in comparison with doping methods, it may be a simpler method of observing energy shifts in solvation effects. Further investigation into spectral diffusion for films under compression indicates a change in spectral diffusion rate due to change in molecular packing density. Comparisons were made between spectral diffusion rates for films under pressure and films of different doping concentrations. Initial measurements of pressure effects on exciplex charge-transfer states in bulk heterojunction films are performed to show change in emission lifetimes. This work could provide a better understanding of the singlet-triplet exciton coupling rates and have a significant impact on device optimization for organic light-emitting diodes (OLEDs) and solar cell applications.
by Wendi Chang.
S.M.
Wasapinyokul, Kamol. "Effects of illumination on the properties of organic field-effect transistors." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609509.
Повний текст джерелаJin, Jiyang. "Synthesis of Novel Hydrogen-Bonding Unit for Organic Field-Effect Transistors." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460047707.
Повний текст джерелаBraga, Daniele. "Charge transport properties of organic semiconductors : application to field effect transistors." Paris 7, 2009. http://www.theses.fr/2009PA077157.
Повний текст джерелаIn order to go deeper in the knowledge of the fundamentals of Organic Field Effect Transistors (OFETs), we have characterized different typologies of OFETs using rubrene single crystals. The latter are highly ordered organic semiconductors with which high mobility transistors can be fabricated. First we have obtained a detailed picture about the properties of a rubrene single crystal, by analyzing the current-voltage (I-V) characteristics of symmetric diodes with the Space Charge Limited Current (SCLC) theory. A low density of defects and a low density of intrinsic thermally generated carriers have been found to characterize this material. On this basis, we have analyzed metal-semiconductor-field-effect-transistors (MESFETs). These non-conventional devices have been proved to be efficient organic FETs, in which the process of charge carrier injection from the ohmic source contact is controlled by the voltage applied to a non-ohmic gate electrode. Finally, metal-insulator-semiconductor field effect ; transistors (MISFETs) have been considered. The (I-V) trend below the threshold voltage is not exponential, as predicted by the inorganic theory; instead, it is linear with the gate voltage and it follows a pseudo-exponential behaviour only in a narrow transition region. An alternative semi-analytical description has been provided here by taking into account the effect of a localized trap level on the distribution of free charges. The presence of this discrete trap level was highlighted by the previously conducted SCLC analysis
Chien, Yu-Mo 1980. "Survey of techniques for improving performance of organic transistors." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100224.
Повний текст джерелаThrough experimental results, it is clear that thermal annealing increases charge carrier mobility of P3HT OFETs. On average an increase of four times in charge mobility was observed after thermal annealing was performed. Dip coated samples also resulted in higher mobility values than spin coated samples. Highest charge mobility value achieved were was ∼0.02 cm2/Vs for dip coated samples, where as the highest value for spin coated devices was around 6e-3 cm2/Vs.
"Dry" stamping of a PDMS devices yielded devices with higher mobility values by around 100% compared to unstamped counterparts. These devices also exhibited lower parasitic leakage currents.
Devices doped with FeCl3 did not perform very well. It is suspected that it was increased so much that it became impossible to turn off the devices.
Chen, Hang. "Modulation Effects on Organic Electronics." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7594.
Повний текст джерелаGranger, Devin B. "ACENES, HETEROACENES AND ANALOGOUS MOLECULES FOR ORGANIC PHOTOVOLTAIC AND FIELD EFFECT TRANSISTOR APPLICATIONS." UKnowledge, 2017. http://uknowledge.uky.edu/chemistry_etds/76.
Повний текст джерелаCastro, Carranza Alejandra. "Umem-based capacitance model for organic field effect transistors: development and implementation." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/111164.
Повний текст джерелаWe developed a new charge and capacitance analytical compact model for organic field effect transistors (OFETs) which we have called UBCM. The model is continuous and valid in all device operation regimes, i.e. accumulation, partial depletion and total depletion. It operates at low and medium frequencies since a quasi-static operation is assumed. The parameters applied in UBCM are analytically extracted from the current-voltage (I-V) characteristics of the OFETs using the unified model and extraction method (UMEM), thus the capacitance model is consistent with the I-V one. The overlap capacitance effect is taken into account and the frequency dependence is considered empirically by means of the insulator permittivity. Comparisons between modeled and experimental gate-to-channel capacitances of OTFTs based on different materials show the validity of the model. Finally, UBCM was implemented in circuit simulators by means of its Verilog-A and Spice codes to simulate organic inverters.
Pérez, Rodríguez Ana. "Nanoscale interpretation of performances in organic solar cells and field effect transistors." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/565824.
Повний текст джерелаTwo of the main challenges in organic electronic devices are the semiconducting layer morphology and the interface properties. Particularly, the interfaces formed by the semiconducting organic layer and the metallic electrodes strongly influence the performance of the devices. Thus, a strong effort has been devoted to improve these interfaces by different approaches such as self assembled monolayers (SAMs), layer of metalic oxides or contact doping. Concerning the morphology, it has been proven that it plays a fundamental role in exciton dissociation, charge collection and recombination in organic solar cells (OSC), as well as in the transport properties in organic field effect transistors (OFETs). In this work we make use of atomic force microscopy (AFM) and, in a lesser extent, of other surface characterization techniques for the study of surfaces and interfaces that conform organic electronic devices. In particular, we focus on the use of friction force microscopy (FFM), conductive atomic force microscopy (C-AFM) and Kelvin probe force microscopy (KPFM) operating modes on OSC and OFETs devices with the goal of correlating the nanoscale characterization with the macroscopic performance of the devices. This thesis is organized in the following way: the motivations of this work are presented in Chapter 1. In Chapter 2 a brief theoretical introduction on organic semiconductors and the concept of self assembly and nanostructuration is given, while in Chapter 3 the techniques employed during this thesis as well as the used methodologies are described. The results are presented in the Chapters 4, 5, 6 and 7. In Chapter 4 we study in detail the physical origin behind Transverse Shear Microscopy (TSM). By combining experimental data with simulations, we prove that the TSM signal has a dissipative origin and we use the technique to obtain the crystalline orientation of tip-induced grown PTCDI-C8 islands. In Chapter 5 we focus on the effect of hole transport layers (HTLs) for both organic and perovskites solar cells. For bulk-heterojunction solar cells (BHJ) we prove that the use of phosphonic acid self assembled monolayers (SAMs) changes the workfunction of the ITO cathode in a favourable way, but also induces a charge accumulation density at the interface with detrimental effects for the cell performance. In perovskite solar cells, despite using newly synthesized HTL with more favourable HOMO position, the energy level alignment at the interface with the TiO2 results less favourable leading to worse photovoltaic device properties. Chapter 6 is devoted to the solvent vapor annealing (SVA) effect on the crystallinity and vertical phase separation on oligothiophene bulkheterojunction solar cells. We prove that, upon SVA, the oligomer domains present better crystallinity while the fullerene domains increase in size, enhancing the photovoltaic performance of the devices. In Chapter 7, a nanoscale characterization by means of FFM was correlated with the device performance for C8-BTBT:PS OFETs, providing with a picture at the nanoscale of the organic films vertical phase separation. By means of KPFM, maps of the surface potential of the OFETs were obtained, allowing us to extract contact resistance and charge mobility values for different electrodes, concluding that the contact resistance is the critical factor limiting the devices performance. Finally, in Chapter 8, the main conclusions of this thesis will be collected.
Irugulapati, Harista. "Fused Arenes-Based Molecular and Polymeric Materials for Organic Field Effect Transistors." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1255.
Повний текст джерелаPaulus, Fabian [Verfasser], and Uwe H. F. [Akademischer Betreuer] Bunz. "N-Heteroacenes in Organic Field-Effect Transistors / Fabian Paulus ; Betreuer: Uwe Bunz." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180615247/34.
Повний текст джерелаKyndiah, Adrica <1987>. "Interfacial interactions, charge transport and growth phenomena in Organic Field Effect Transistors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7100/.
Повний текст джерелаLee, Yongjeong. "Gaussian density of states driven numerical modeling of organic field-effect transistors." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX043.
Повний текст джерелаAlthough the device physics of organic field-effect transistors (OFETs) has been widely studied, the analysis with energetic distribution of the density-of-states (DOS) is still lacking in spite of the disordered nature of organic semiconductors. Because charge transport and injection take place at the Gaussian DOS, this distinctive energetic structure of organic semiconductors could make the charge-accumulation process, and hence the device operation, different. This thesis is dedicated to understanding the effect of Gaussian DOS on device parameters of OFETs, the threshold voltage, charge-carrier mobility and injection barrier via numerical finite-element based 2D simulations and experimental validation. The threshold voltage is comprehended by the charge trapping into the secondary Gaussian trap DOS as well as the intrinsic Gaussian DOS. We show that the overlap of two Gaussian DOSs due to the disorder induces specific threshold behaviors of OFETs. Second, the hopping transport is studied via Gaussian disordered model (GDM) on random spatial sites of organic semiconductors. This model can offer a precise result over GDM with cubic lattice. Also, we propose a correct parametrization of the model for wide range of materials from polymers to small molecules. Lastly, charge-based and transport-based injection barrier are studied and compared with Gaussian DOS. The advantages and limits of each model are evaluated