Interfaces of Electrical Contacts in Organic Semiconductor Devices

Interfaces of Electrical Contacts in Organic Semiconductor Devices

Author: Korhan Demirkan

Publisher: ProQuest

Published: 2008

Total Pages:

ISBN-13: 9780549752196

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Progress in organic semiconductor devices relies on better understanding of interfaces as well as material development. The engineering of interfaces that exhibit low resistance, low operating voltage and long-term stability to minimize device degradation is one of the crucial requirements. Photoelectron spectroscopy is a powerful technique to study the metal-semiconductor interfaces, allowing: (i) elucidation of the energy levels of the semiconductor and the contacts that determine Schottky barrier height, (ii) inspection of electrical interactions (such as charge transfer, dipole formation, formation of induced density of states or formation of polaron/bi-polaron states) that effect the energy level alignment, (iii) determination of interfacial chemistry, and (iv) estimation of interface morphology. In this thesis, we have used photoelectron spectroscopy extensively for detailed analysis of the metal organic semiconductor interfaces. In this study, we demonstrate the use of photoelectron spectroscopy for construction of energy level diagrams and display some results related to chemical tailoring of materials for engineering interfaces with lowered Schottky barriers. Following our work on the energy level alignment of poly(p-phenyene vinylene) based organic semiconductors on various substrates [Au, indium tin oxide, Si (with native oxide) and Al (with native oxide)], we tested controlling the energy level alignment by using polar self assembled molecules (SAMs). Photoelectron spectroscopy showed that, by introducing SAMs on the Au surface, we successfully changed the effective work function of Au surface. We found that in this case, the change in the effective work function of the metal surface was not reflected as a shift in the energy levels of the organic semiconductor, as opposed to the results achieved with different substrate materials. To investigate the chemical interactions at the metal/organic interface, we studied the metallization of poly(2-methoxy-5,2'-ethyl-hexyloxy-phenylene vinylene) (MEH-PPV), polystyrene (PS) and ozone treated polystyrene (PS-O3) surfaces by thermal deposition of aluminum. Photoelectron spectroscopy showed the degree of chemical interaction between Al and each polymer, for MEH-PPV, the chemical interactions were mainly through the C-O present in the side chain of the polymer structure. The chemical interaction of Al with polystyrene was less significant, but it showed a dramatic increase after ozone treatment of the polystyrene surface (due to the formation of exposed oxygen sites). Formation of metal oxide and metal-organic compound is detected during the Al metallization of MEH-PPV and ozone-treated PS surfaces. Our results showed that the condensation of Al on polymer surfaces is highly dependent on surface reactivity. Enormous differences were observed for the condensation coefficient of Al on PS and PS-O3 surfaces. For the inert PS surface, results showed that Al atoms poorly wet the polymer surface and form distributed clusters at the surface. Results on reactive polymer surfaces suggest morphology reminiscent of a Stranski- Krastanov-type growth and high contact area. Many studies have shown that the insertion of a thin interlayer of the oxide or fluoride of alkali or alkaline metals between the low work function electrode and the organic semiconductor layers dramatically lowers the onset voltage and increases the efficiency compared to identical devices without the insulating layer. Various modes have been suggested for the mechanism of device performance enhancement. We have investigated the chemical and electrical interaction of (i) LiF with MEH-PPV, (ii) Al with MEH-PPV in the presence of a thin LiF layer at the interface, and finally (iii) the interaction of Al with LiF. AFM and XPS data showed that LiF forms island on the surface. Our data in agreement with various existing models suggested the (i) alteration in the electronic properties under applied bias, (ii) doping of the organic semiconductor, (iii) formation of metal alloy (Au-Li). In addition to the possible electrical modifications at the interface suggested previously, our data also suggest a change in the film growth on LiF modified surfaces.


Nanoscale Interface for Organic Electronics

Nanoscale Interface for Organic Electronics

Author: Mitsumasa Iwamoto

Publisher: World Scientific

Published: 2011

Total Pages: 387

ISBN-13: 9814322482

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This book treats the important issues of interface control in organic devices in a wide range of applications that cover from electronics, displays, and sensors to biorelated devices. This book is composed of three parts: Part 1, Nanoscale interface; Part 2, Molecular electronics; Part 3, Polymer electronics.


Wspc Reference On Organic Electronics, The: Organic Semiconductors (In 2 Volumes)

Wspc Reference On Organic Electronics, The: Organic Semiconductors (In 2 Volumes)

Author: Seth R Marder

Publisher: World Scientific

Published: 2016-06-24

Total Pages: 896

ISBN-13: 9814699241

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This 2-volume set provides the reader with a basic understanding of the foundational concepts pertaining to the design, synthesis, and applications of conjugated organic materials used as organic semiconductors, in areas including organic photovoltaic devices, light-emitting diodes, field-effect transistors, spintronics, actuation, bioelectronics, thermoelectrics, and nonlinear optics.While there are many monographs in these various areas, the emphasis here is both on the fundamental chemistry and physics concepts underlying the field of organic semiconductors and on how these concepts drive a broad range of applications. This makes the volumes ideal introductory textbooks in the subject. They will thus offer great value to both junior and senior scientists working in areas ranging from organic chemistry to condensed matter physics and materials science and engineering.Number of Illustrations and Tables: 168 b/w illus., 242 colour illus., 13 tables.


Organic Semiconductors in Sensor Applications

Organic Semiconductors in Sensor Applications

Author: Daniel A. Bernards

Publisher: Springer Science & Business Media

Published: 2008-02-22

Total Pages: 302

ISBN-13: 3540763147

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Organic semiconductors offer unique characteristics which have prompted the application of organic semiconductors and their devices in physical, chemical, and biological sensors. This book covers this emerging field by discussing both optically- and electrically-based sensor concepts. Novel transducers based on organic light-emitting diodes and organic thin-film transistors, as well as systems-on-a-chip architectures are presented. Functionalization techniques are also outlined.


Handbook of Surfaces and Interfaces of Materials, Five-Volume Set

Handbook of Surfaces and Interfaces of Materials, Five-Volume Set

Author: Hari Singh Nalwa

Publisher: Elsevier

Published: 2001-10-26

Total Pages: 1915

ISBN-13: 0080533825

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This handbook brings together, under a single cover, all aspects of the chemistry, physics, and engineering of surfaces and interfaces of materials currently studied in academic and industrial research. It covers different experimental and theoretical aspects of surfaces and interfaces, their physical properties, and spectroscopic techniques that have been applied to a wide class of inorganic, organic, polymer, and biological materials. The diversified technological areas of surface science reflect the explosion of scientific information on surfaces and interfaces of materials and their spectroscopic characterization. The large volume of experimental data on chemistry, physics, and engineering aspects of materials surfaces and interfaces remains scattered in so many different periodicals, therefore this handbook compilation is needed.The information presented in this multivolume reference draws on two decades of pioneering research on the surfaces and interfaces of materials to offer a complete perspective on the topic. These five volumes-Surface and Interface Phenomena; Surface Characterization and Properties; Nanostructures, Micelles, and Colloids; Thin Films and Layers; Biointerfaces and Applications-provide multidisciplinary review chapters and summarize the current status of the field covering important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniques with contributions from internationally recognized experts from all over the world. Fully cross-referenced, this book has clear, precise, and wide appeal as an essential reference source long due for the scientific community. The complete reference on the topic of surfaces and interfaces of materialsThe information presented in this multivolume reference draws on two decades of pioneering researchProvides multidisciplinary review chapters and summarizes the current status of the fieldCovers important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniquesContributions from internationally recognized experts from all over the world


Defects in Organic Semiconductors and Devices

Defects in Organic Semiconductors and Devices

Author: Thien-Phap Nguyen

Publisher: John Wiley & Sons

Published: 2023-08-29

Total Pages: 292

ISBN-13: 1786309262

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Defects play a key role in the physical properties of semiconductors and devices, and their identification is essential in assessing the reliability of electronic devices. Defects in Organic Semiconductors and Devices introduces the fundamental aspects of defects in organic semiconductors and devices in relation to the structure of materials and architecture of electronic components. It covers the topics of defect formation and evolution, defect measurement techniques and their adaption to organic devices, the effects of defects on the physical properties of materials and their effects on the performance and lifetime of organic devices. Identifying defects and determining their characteristics in the structure of organic devices such as OLEDs, OFETs and OPVs make it possible to better understand degradation processes and develop solutions to improve the reliability of such devices. This book is intended for researchers and students in university programs or engineering schools who are specializing in electronics, energy and materials.


Introduction to Organic Electronic Devices

Introduction to Organic Electronic Devices

Author: Guangye Zhang

Publisher: Springer Nature

Published: 2022-10-13

Total Pages: 314

ISBN-13: 9811960917

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This book comprehensively describes organic electronic devices developed in the past decades. It not only covers the mainstream devices including organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), and organic thin-film transistors (OTFTs) but also includes devices of recent interest such as organic immune transistors, organic photocatalysis devices, and themoelectrical devices. The book starts from the introduction of basic theory of organic semiconductor materials and devices, which acquaints the readers with the concepts of each type of device described in the following chapters. It also discusses the working principles, device layout, and fabrication process of these devices. The book is intended for undergraduate and postgraduate students who are interested in organic electronics, researchers/engineers working in the field of organic electronic devices/systems.


Handbook of Flexible Organic Electronics

Handbook of Flexible Organic Electronics

Author: Stergios Logothetidis

Publisher: Elsevier

Published: 2014-12-03

Total Pages: 483

ISBN-13: 1782420436

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Organic flexible electronics represent a highly promising technology that will provide increased functionality and the potential to meet future challenges of scalability, flexibility, low power consumption, light weight, and reduced cost. They will find new applications because they can be used with curved surfaces and incorporated in to a number of products that could not support traditional electronics. The book covers device physics, processing and manufacturing technologies, circuits and packaging, metrology and diagnostic tools, architectures, and systems engineering. Part one covers the production, properties and characterisation of flexible organic materials and part two looks at applications for flexible organic devices. - Reviews the properties and production of various flexible organic materials. - Describes the integration technologies of flexible organic electronics and their manufacturing methods. - Looks at the application of flexible organic materials in smart integrated systems and circuits, chemical sensors, microfluidic devices, organic non-volatile memory devices, and printed batteries and other power storage devices.


Organic Electronics 1

Organic Electronics 1

Author: Thien-Phap Nguyen

Publisher: John Wiley & Sons

Published: 2021-03-12

Total Pages: 208

ISBN-13: 1119818923

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Due to their special properties, organic semiconductors enable the development of large-area, low-cost devices, paving the way for flexible and nomadic applications that advantageously replace those made with traditional semiconductors. This book describes the properties and deposition methods of organic semiconductors, transparent conductive materials or metals which are used in the fabrication of organic devices. The physical processes (optical, electrical and interface) that control the mechanisms in the formation and transport of the charge carriers of the materials are studied and explained in detail. Organic Electronics 1 introduces the fundamental and applied aspects of the field of organic electronics. It is intended for researchers and students in university programs or engineering schools specializing in electronics, energy and materials.


Organic Thin Film Transistor Integration

Organic Thin Film Transistor Integration

Author: Flora Li

Publisher: John Wiley & Sons

Published: 2011-03-21

Total Pages: 258

ISBN-13: 3527634452

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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.