Download or read book Optical Properties of Organic Semiconductors written by and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties of Organic Semiconductors from Submonolayers to Crystalline Films written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the optical properties of films of the organic semiconductors PTCDA (3,4:9,10-perylene-tetracarboxylic dianhydride) and HBC (peri-hexabenzocoronene), prepared by Organic Molecular Beam Expitaxy (OMBE), on different substrates by means of Differential Reflectance Spectroscopy (DRS). The optical setup enables us to directly follow the thickness dependent optical properties of the organic films, starting from submonolayer coverage up to thicker films on the order of 20 monolayers (ML) film thickness. Due to the different optical nature of the different substrates used, i.e., mica, glass, Au(111), and HOPG, the direct interpretation of the DRS signal is not feasible. Therefore, we have proposed a method by which the calculation of the optical constants n (index of refraction) and k (absorption index) of thin films on arbitrary substrates from just one spectral measurement (in our case the DRS) becomes possible. The results fulfill a priori a Kramers-Kronig consistency and no specific model is needed to express the spectral behavior of the optical constants. Based on our method, we have successfully calculated the optical constants, and therefore the absorption behavior, of films of different thickness of PTCDA on mica, glass, Au(111), and HOPG, as well as of HBC on mica, glass, and HOPG. Extrinsic effects due to island growth or the presence of a polarizable substrate (screening) have been accounted for. We have introduced a finite dipole model which considers the extended geometry and anisotropy of the organic molecules. The calculated absorption behavior is discussed in great detail in terms of spectral changes with varying film thickness, different growth modes, degree of ordering of the films, interactions with the substrates and oscillator strength. A direct observation of a monomer-dimer transition in solid films could be observed for the first time. Our results indicate an exciton delocalization over about 4 molecules for both molecules.
Download or read book Optical properties of organic semiconductors From sub monolayers to crystalline films written by and published by Cuvillier Verlag. This book was released on 2006-05-10 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the optical properties of films of the organic semiconductors PTCDA and HBC, prepared by Organic Molecular Beam Expitaxy (OMBE), on different substrates by means of Differential Reflectance Spectroscopy (DRS). The optical setup used [51] allows to characterize the samples in situ and during the film growth. This enables us to directly follow the thickness dependent optical properties of the organic films, starting from submonolayer coverage up to thicker films on the order of 20 monolayers (ML) film thickness. However, due to the different optical nature of the different substrates used, i.e., mica, glass, Au(111), and HOPG, the DRS signal can not directly be interpreted in terms of the absorption of the films. Rather, the optical constants n (index of refraction) and k (absorption index) of the organic films have to be calculated to be able to discuss the spectral absorption of the films. We have proposed a method by which the calculation of the optical constants of thin films on arbitrary substrates from just one spectral measurement (in our case the DRS) becomes possible. The results fulfill a priori a Kramers-Kronig consistency, characteristic for physically meaningful values of the optical constants, and no specific model is needed to express the spectral behavior of the optical constants. Still, the requirement that the absorption index has to approach zero sufficiently at the measurement intervals restricts the application of our method to a class of materials, which exhibit distinct and well-separated absorption bands, like e.g. organic semiconductors. By means of appropriate extrapolation procedures, the method is able to account for small non-zero values of the absorption index at the boundaries of the measurement interval. Although we exclusively discussed the application of our method to differential reflectance spectra, it is anticipated that it works for all other optical quantities likewise.
Download or read book Optical Properties of Crystalline and Amorphous Semiconductors written by Sadao Adachi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Principles presents an introduction to the fundamental optical properties of semiconductors. This book presents tutorial articles in the categories of materials and fundamental principles (Chapter 1), optical properties in the reststrahlen region (Chapter 2), those in the interband transition region (Chapters 3 and 4) and at or below the fundamental absorption edge (Chapter 5). Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Principles is presented in a form which could serve to teach the underlying concepts of semiconductor optical properties and their implementation. This book is an invaluable resource for device engineers, solid-state physicists, material scientists and students specializing in the fields of semiconductor physics and device engineering.
Download or read book Optical Properties of Organic Semiconductor Thin Films written by Ute Heinemeyer and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties and Applications of Semiconductors written by Inamuddin and published by CRC Press. This book was released on 2022-07-18 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductors with optical characteristics have found widespread use in evolving semiconductor photovoltaics, where optical features are important. The industrialization of semiconductors and their allied applications have paved the way for optical measurement techniques to be used in new ways. Due to their unique properties, semiconductors are key components in the daily employed technologies in healthcare, computing, communications, green energy, and a range of other uses. This book examines the fundamental optical properties and applications of semiconductors. It summarizes the information as well as the optical characteristics and applicability of semiconductors through an in-depth review of the literature. Accomplished experts in the field share their knowledge and examine new developments. FEATURES Comprehensive coverage of all types of optical applications using semiconductors Explores relevant composite materials and devices for each application Addresses the optical properties of crystalline and amorphous semiconductors Describes new developments in the field and future potential applications Optical Properties and Applications of Semiconductors is a comprehensive reference and an invaluable resource for engineers, scientists, academics, and industry R&D teams working in applied physics.
Download or read book Optical Constants of Crystalline and Amorphous Semiconductors written by Sadao Adachi and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 725 pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge of the refractive indices and absorption coefficients of semiconductors is especially import in the design and analysis of optical and optoelectronic devices. The determination of the optical constants of semiconductors at energies beyond the fundamental absorption edge is also known to be a powerful way of studying the electronic energy-band structures of the semiconductors. The purpose of this book is to give tabulated values and graphical information on the optical constants of the most popular semiconductors over the entire spectral range. This book presents data on the optical constants of crystalline and amorphous semiconductors. A complete set of the optical constants are presented in this book. They are: the complex dielectric constant (E=e.+ieJ, complex refractive index (n*=n+ik), absorption coefficient (a.), and normal-incidence reflectivity (R). The semiconductor materials considered in this book are the group-IV elemental and binary, llI-V, IT-VI, IV-VI binary semiconductors, and their alloys. The reader will fmd the companion book "Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Principles" useful since it emphasizes the basic material properties and fundamental prinCiples.
Download or read book Molecular Orientation and Emission Characteristics of Ir Complexes and Exciplex in Organic Thin Films written by Chang-Ki Moon and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis considers molecular orientation in thin films and introduces an optical model describing this orientation as applied to organic light-emitting diodes (OLEDs). It also describes the electronic structure of intermolecular charge transfer excitons correlated to molecular orientation in solids. It has long been known that molecular orientation influences the electrical and optical properties of molecular films. One notable example is in liquid crystals where rigid rod or disk shaped molecules are commonly used. Understanding the origin of the molecular orientation and its control by surface treatment and electric field resulted in the development of liquid crystal displays. The same thing has happened in organic electronics, and considerable effort has been devoted to understanding and controlling molecular orientation in solid films to improve charge carrier mobility and light absorption, ultimately to improve the performance of organic solar cells and thin film transistors. In contrast, less attention has been paid to molecular orientation and its influence on the characteristics of OLEDs, probably because of the use of amorphous films rather than micro-crystalline films, and it is only in recent years that some molecular films are known to have preferred orientation. This thesis addresses this topic, focusing on OLEDs, describing the origin and control of the orientation of phosphorescent Ir complexes possessing spherical shape rather than rod or disk shape, the simulation of the optical characteristics of OLEDs influenced by preferred molecular orientation, and finally the orientation of intermolecular charge transfer excitons and its correlation to electronic structures in thin films.
Download or read book Investigations of the Optical and Electronic Properties of Crystalline Organic Semiconductors written by and published by . This book was released on 1996 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the course of this program, major advances have been made in our understanding of the growth and optical properties of organic nanostructures. For example, we have found that a clear indication of quasi-epitaxial growth of an organic molecule is failure of the epitaxial layer to reduce strain by the generation of defects as films thickness is increased. Furthermore, studies of the optical spectra of closely packed molecules such as PTCDA indicate that organic nanostructures (such as multiple quantum wells) can be used to change the electronic and optical properties of organic materials in much the same manner as in inorganic semiconductors. Further, we have demonstrated high efficiency organic light emitting devices, as well as the invented the process of organic vapor phase deposition (OVPD) for achieving ordered growth of organic salts for nonlinear optics applications.
Download or read book Optical Properties of Semiconductors written by N. G. Basov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical and Optical Properties of Semiconductors written by D. V. Skobel tsyn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Electronic and Optical Properties of Amorphous Organic Semiconductors written by Marc Baldo and published by . This book was released on 2001 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Linear and Nonlinear Optical Properties of Organic Semiconductors written by Ian Munro Craig and published by . This book was released on 2010 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electronic and Optical Properties of Organic Crystals Polymers and Semiconductors written by Murilo Louzeiro Tiago and published by . This book was released on 2003 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoconductive and Optical Properties of Organic Molecular Crystals written by Arthur Aaron Bright and published by . This book was released on 1973 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties of Photonic Crystals written by Kazuaki Sakoda and published by Springer. This book was released on 2009-09-02 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive textbook on the optical properties of photonic crystals. It deals not only with the properties of the radiation modes inside the crystals but also with their peculiar optical response to external fields. Has consistently been a good seller (sometimes best-seller) at Optical Society of America meetings. Important recent developments such as the enhancement of stimulated emission, second harmonic generation, quadrature-phase squeezing, and low-threshold lasing are also treated in detail and made understandable. Numerical methods are also emphasized. Provides both an introduction for graduate and undergraduate students and also key information for researchers in this field. The second edition features a new chapter on superfluorescence and updated text and references throughout.
Download or read book Interplay of Ordering Behavior and Optical Properties in Organic Semiconductor Blends written by Katharina Broch and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
