Download or read book Quantum Confinement Carrier Dynamics and Interfacial Processes in Nanostructured Direct written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of semiconductor clusters precipitated in an insulated matrix was investigated. Semiconductor compositions of CdTe, Si and Ge were studies and the insulating matrix was amorphous SiO2. As a function of size, quantum confinement effects were observed in all three composite systems. However significant differences were observed between the direct-gap column 2-6 semiconductors and the indirect-gap column 4 semiconductors. As observed by others, the direct-gap 2-6 semiconductors showed a distinct saturation in the energy-gap blue shift with decreasing size. Theoretical studies using a 20-band k dot p calculation of the electronic and valence bands for a 3-dimensionally confined CdTe semiconductor showed that mixing of the conduction band states leads to a flattening of the central valley. This increases the electron mass drastically and saturates the size dependent blue shift in the bandgap. In contrast, the blue shift in the Si and Ge nanocrystals showed no sign of saturation and increased drastically with decreasing size. In fact, Si and Ge crystals were formed with blue shift values that moved the bandgap to the near UV region. We examined the absorption curves to determine whether the bandgap was direct or indirect in the quantum dots. The results are that the absorption shows an indirect gap for all but the smallest Si crystals and an indirect gap for all Ge crystals. Raman studies showed negligible size dependence due to a lack of phonon confinement in the matrix embedded clusters. Exciton saturation and recovery times were found to be very short (of the order of 400fs) and are the fastest reported for any quantum dot system. Work to examine the type of confinement obtained in a matrix that consists of a transparent conductor is under way. Studies of the photoinduced absorption change in GeSe glasses showed a significant effect of photodarkening, regardless of composition. The photodarkening effect appears to be composed of permanent and transient effects, presumed to be associated with photo-induced structural changes in the glass. The transient effects appear to have recovery times in at least two different time scales--one in minutes and one in less than a microsecond. Time-resolved studies are under way to determine the structural origin of each photodarkening effect.
Download or read book Quantum Confinement Carrier Dynamics and Interfacial Processes in Nanostructured Direct indirect gap Semiconductor glass Composites written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of semiconductor clusters precipitated in an insulated matrix was investigated. Semiconductor compositions of CdTe, Si and Ge were studies and the insulating matrix was amorphous SiO[sub 2]. As a function of size, quantum confinement effects were observed in all three composite systems. However significant differences were observed between the direct-gap column 2-6 semiconductors and the indirect-gap column 4 semiconductors. As observed by others, the direct-gap 2-6 semiconductors showed a distinct saturation in the energy-gap blue shift with decreasing size. Theoretical studies using a 20-band k dot p calculation of the electronic and valence bands for a 3-dimensionally confined CdTe semiconductor showed that mixing of the conduction band states leads to a flattening of the central valley. This increases the electron mass drastically and saturates the size dependent blue shift in the bandgap. In contrast, the blue shift in the Si and Ge nanocrystals showed no sign of saturation and increased drastically with decreasing size. In fact, Si and Ge crystals were formed with blue shift values that moved the bandgap to the near UV region. We examined the absorption curves to determine whether the bandgap was direct or indirect in the quantum dots. The results are that the absorption shows an indirect gap for all but the smallest Si crystals and an indirect gap for all Ge crystals. Raman studies showed negligible size dependence due to a lack of phonon confinement in the matrix embedded clusters. Exciton saturation and recovery times were found to be very short (of the order of 400fs) and are the fastest reported for any quantum dot system. Work to examine the type of confinement obtained in a matrix that consists of a transparent conductor is under way. Studies of the photoinduced absorption change in GeSe glasses showed a significant effect of photodarkening, regardless of composition. The photodarkening effect appears to be composed of permanent and transient effects, presumed to be associated with photo-induced structural changes in the glass. The transient effects appear to have recovery times in at least two different time scales--one in minutes and one in less than a microsecond. Time-resolved studies are under way to determine the structural origin of each photodarkening effect.
Download or read book Nanostructured Materials and Nanotechnology written by Hari Singh Nalwa and published by Gulf Professional Publishing. This book was released on 2002 with total page 859 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology Provides comprehensive coverage of the dominant technology of the 21st century Written by a truly international list of contributors.
Download or read book Handbook of Nanostructured Materials and Nanotechnology Five Volume Set written by Hari Singh Nalwa and published by Academic Press. This book was released on 1999-10-29 with total page 3593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured materials is one of the hottest and fastest growing areas in today's materials science field, along with the related field of solid state physics. Nanostructured materials and their based technologies have opened up exciting new possibilites for future applications in a number of areas including aerospace, automotive, x-ray technology, batteries, sensors, color imaging, printing, computer chips, medical implants, pharmacy, and cosmetics. The ability to change properties on the atomic level promises a revolution in many realms of science and technology. Thus, this book details the high level of activity and significant findings are available for those involved in research and development in the field. It also covers industrial findings and corporate support. This five-volume set summarizes fundamentals of nano-science in a comprehensive way. The contributors enlisted by the editor are at elite institutions worldwide. Key Features * Provides comprehensive coverage of the dominant technology of the 21st century * Written by 127 authors from 16 countries, making this truly international * First and only reference to cover all aspects of nanostructured materials and nanotechnology
Download or read book Characterization of Semiconductor Heterostructures and Nanostructures written by S. Sanguinetti and published by Elsevier Inc. Chapters. This book was released on 2013-04-11 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self Assembly of Nanostructures written by Stefano Bellucci and published by Springer Science & Business Media. This book was released on 2011-10-27 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the third volume in a series of books on selected topics in Nanoscale Science and Technology based on lectures given at the well-known Istituto Nazionale di Fisica Nucleare (INFN) schools of the same name. The present set of notes stems in particular from the participation and dedication of prestigious lecturers, such as Nunzio Motta, Fulvia Patella, Alexandr Toropov, and Anna Sgarlata. All lectures have been carefully edited and reworked, taking into account extensive follow-up discussions. A tutorial lecture by Motta et al. presents the analysis of the Poly(3-hexylthiophene) self assembly on carbon nanotubes and discusses how the interaction between the two materials forms a new hybrid nanostructure, with potential application to future solar cells technology. In their contribution, Patella et al. review quantum dots of III-V compounds, which offer appealing perspectives for more sophisticated applications in new generation devices such as single-photon emitters for nano-photonics and quantum computing. Focusing on self-assembled quantum dots, the chapter by Alexandr Toropov et al. provides a comprehensive review of some important aspects in the formation of quantum dots and presents the results of the authors’ extensive investigation of the features of droplet epitaxy. The fourth contribution, by Sgarlata et al., focuses on recent progress toward controlled growth of self-assembled nanostructures, dealing with the shaping, ordering and localization in Ge/Si heteroepitaxy and reviewing recent results on the self-organization of Ge nanostructures at Si surfaces.
Download or read book Characterization of Semiconductor Heterostructures and Nanostructures written by Giovanni Agostini and published by Newnes. This book was released on 2013-04-11 with total page 829 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of Semiconductor Heterostructures and Nanostructures is structured so that each chapter is devoted to a specific characterization technique used in the understanding of the properties (structural, physical, chemical, electrical etc..) of semiconductor quantum wells and superlattices. An additional chapter is devoted to ab initio modeling. The book has two basic aims. The first is educational, providing the basic concepts of each of the selected techniques with an approach understandable by advanced students in Physics, Chemistry, Material Science, Engineering, Nanotechnology. The second aim is to provide a selected set of examples from the recent literature of the TOP results obtained with the specific technique in understanding the properties of semiconductor heterostructures and nanostructures. Each chapter has this double structure: the first part devoted to explain the basic concepts, and the second to the discussion of the most peculiar and innovative examples. The topic of quantum wells, wires and dots should be seen as a pretext of applying top level characterization techniques in understanding the structural, electronic etc properties of matter at the nanometer (and even sub-nanometer) scale. In this respect it is an essential reference in the much broader, and extremely hot, field of Nanotechnology. Comprehensive collection of the most powerful characterization techniques for semiconductors heterostructures and nanostructures Most of the chapters are authored by scientists that are world-wide among the top-ten in publication ranking of the specific field Each chapter starts with a didactic introduction on the technique The second part of each chapters deals with a selection of top examples highlighting the power of the specific technique to analyse the properties of semiconductors heterostructures and nanostructures
Download or read book Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics written by Mohamed Henini and published by Elsevier Science. This book was released on 2008 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1969, Leo Esaki (1973 Nobel Laureate) and Ray Tsu from IBM, USA, proposed research on “man-made crystals” using a semiconductor superlattice (a semiconductor structure comprising several alternating ultra-thin layers of semiconductor materials with different properties). This invention was perhaps the first proposal to advocate the engineering of a new semiconductor material, and triggered a wide spectrum of experimental and theoretical investigations. However, the study of what are now called low dimensional structures (LDS) began in the late 1970's when sufficiently thin epitaxial layers were first produced following developments in the technology of epitaxial growth of semiconductors, mainly pioneered in industrial laboratories for device purposes. The LDS are materials structures whose dimensions are comparable with inter-atomic distances in solids (i.e. nanometre, nm). Their electronic properties are significantly different from the same material in bulk form. These properties are changed by quantum effects. At the inception of their investigation it was already clear that such structures were of great scientific interest and excitement and their novel properties caused by quantum effects offered potential for application in new devices. Moreover these complex LDS offer device engineers new design opportunities for tailor-made new generation electronic devices. The LDS could be considered as a new branch of condensed matter physics because of the large variety of possible structures and the changes in the physical processes. One of the promising fabrication methods to produce and study structures with a dimension less than two such as quantum wires and quantum dots, in order to realise novel devices that make use of low-dimensional confinement effects, is self-organisation. Self-assembled nanostructured materials offer a number of advantages over conventional material technologies in a wide-range of sectors. Clearly, future research work on self-assembled nanostructures will connect diverse areas of material science, physics, chemistry, electronics and optoelectronics. Key Features: - Contributors are world leaders in the field - Brings together all the factors which are essential in self-organisation of quantum nanostructures - Reviews the current status of research and development in self-organised nanostructured materials - Provides a ready source of information on a wide range of topics - Useful to any scientist who is involved in nanotechnology - Excellent starting point for workers entering the field - Serves as an excellent reference manual
Download or read book Hot Carriers in Semiconductor Nanostructures written by Jagdeep Shah and published by Elsevier. This book was released on 2012-12-02 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonequilibrium hot charge carriers play a crucial role in the physics and technology of semiconductor nanostructure devices. This book, one of the first on the topic, discusses fundamental aspects of hot carriers in quasi-two-dimensional systems and the impact of these carriers on semiconductor devices. The work will provide scientists and device engineers with an authoritative review of the most exciting recent developments in this rapidly moving field. It should be read by all those who wish to learn the fundamentals of contemporary ultra-small, ultra-fast semiconductor devices. Topics covered include Reduced dimensionality and quantum wells Carrier-phonon interactions and hot phonons Femtosecond optical studies of hot carrier Ballistic transport Submicron and resonant tunneling devices
Download or read book Characterization of Semiconductor Heterostructures and Nanostructures written by Carlo Lamberti and published by Elsevier. This book was released on 2008-08-19 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: - Comprehensive collection of the most powerful characterization techniques for semiconductors heterostructures and nanostructures. - Most of the chapters are authored by scientists that are world wide among the top-ten in publication ranking of the specific field. - Each chapter starts with a didactic introduction on the technique. - The second part of each chapters deals with a selection of top examples highlighting the power of the specific technique to analyse the properties of semiconductors heterostructures and nanostructures.
Download or read book Semiconductor Nanocrystals written by Alexander L. Efros and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A physics book that covers the optical properties of quantum-confined semiconductor nanostructures from both the theoretical and experimental points of view together with technological applications. Topics to be reviewed include quantum confinement effects in semiconductors, optical adsorption and emission properties of group IV, III-V, II-VI semiconductors, deep-etched and self assembled quantum dots, nanoclusters, and laser applications in optoelectronics.
Download or read book Ultimate Physics written by Scientific American Editors and published by Scientific American. This book was released on 2016-07-11 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental outlines of the physical world, from its tiniest particles to massive galaxy clusters, have been apparent for decades. Does this mean physicists are about to tie it all up into a neat package? Not at all. Just when you think you’re figuring it out, the universe begins to look its strangest. This eBook, “Ultimate Physics: From Quarks to the Cosmos,” illustrates clearly how answers often lead to more questions and open up new paths to insight. We open with “The Higgs at Last,” which looks behind the scenes of one of the most anticipated discoveries in physics and examines how this “Higgs-like” particle both confirmed and confounded expectations. In “The Inner Life of Quarks,” author Don Lincoln discusses evidence that quarks and leptons may not be the smallest building blocks of matter. Section Two switches from the smallest to the largest of scales, and in “Origin of the Universe,” Michael Turner analyzes a number of speculative scenarios about how it all began. Another two articles examine the mystery of dark energy and some doubts as to whether it exists at all. In the last section, we look at one of the most compelling problems in physics: how to tie together the very small and the very large – quantum mechanics and general relativity. In one article, Stephen Hawking and Leonard Mlodinow argue that a so-called “theory of everything” may be out of reach, and in another, David Deutsch and Artur Ekert question the view that quantum mechanics imposes limits on knowledge, arguing instead that the theory has an intricacy that allows for new, practical technologies, including powerful computers that can reach their true potential.
Download or read book Microprobe Characterization of Optoelectronic Materials written by Juan Jimenez and published by CRC Press. This book was released on 2002-11-15 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each chapter in this book is written by a group of leading experts in one particular type of microprobe technique. They emphasize the ability of that technique to provide information about small structures (i.e. quantum dots, quantum lines), microscopic defects, strain, layer composition, and its usefulness as diagnostic technique for device degradation. Different types of probes are considered (electrons, photons and tips) and different microscopies (optical, electron microscopy and tunneling). It is an ideal reference for post-graduate and experienced researchers, as well as for crystal growers and optoelectronic device makers.
Download or read book Applied Nanophotonics written by Hilmi Volkan Demir and published by Cambridge University Press. This book was released on 2018-11-22 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: An accessible yet rigorous introduction to nanophotonics, covering basic principles, technology, and applications in lighting, lasers, and photovoltaics. Providing a wealth of information on materials and devices, and over 150 color figures, it is the 'go-to' guide for students in electrical engineering taking courses in nanophotonics.
Download or read book Quantum Dot Molecules written by Jiang Wu and published by Springer Science & Business Media. This book was released on 2013-10-28 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantum dot molecule (QDM) is composed of two or more closely spaced quantum dots or “artificial atoms.” In recent years, QDMs have received much attention as an emerging new artificial quantum system. The interesting and unique coupling and energy transfer processes between the “artificial atoms” could substantially extend the range of possible applications of quantum nanostructures. This book reviews recent advances in the exciting and rapidly growing field of QDMs via contributions from some of the most prominent researchers in this scientific community. The book explores many interesting topics such as the epitaxial growth of QDMs, spectroscopic characterization, and QDM transistors, and bridges between the fundamental physics of novel materials and device applications for future information technology. Both theoretical and experimental approaches are considered. Quantum Dot Molecules can be recommended for electrical engineering and materials science department courses on the science and design of advanced and future electronic and optoelectronic devices.
Download or read book Nanostructured and Photoelectrochemical Systems for Solar Photon Conversion written by Mary D. Archer and published by World Scientific. This book was released on 2008 with total page 781 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, expert authors describe advanced solar photon conversion approaches that promise highly efficient photovoltaic and photoelectrochemical cells with sophisticated architectures on the one hand, and plastic photovoltaic coatings that are inexpensive enough to be disposable on the other. Their leitmotifs include light-induced exciton generation, junction architectures that lead to efficient exciton dissociation, and charge collection by percolation through mesoscale phases. Photocatalysis is closely related to photoelectrochemistry, and the fundamentals of both disciplines are covered in this volume.
Download or read book Hot Carriers in Semiconductors written by Karl Hess and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains invited and contributed papers of the Ninth International Conference on Hot Carriers in Semiconductors (HCIS-9), held July 3 I-August 4, 1995 in Chicago, Illinois. In all, the conference featured 15 invited oral presentations, 60 contributed oral presentations, and 105 poster presentations, and an international contingent of 170 scientists. As in recent conferences, the main themes of the conference were related to nonlinear transport in semiconductor heterojunctions and included Bloch oscillations, laser diode structures, and femtosecond spectroscopy. Interesting questions related to nonlinear transport, size quantization, and intersubband scattering were addressed that are relevant to the new quantum cascade laser. Many lectures were geared toward quantum wires and dots and toward nanostructures and mesoscopic systems in general. It is expected that such research will open new horizons to nonlinear transport studies. An attempt was made by the program committee to increase the number of presen tations related directly to devices. The richness of nonlocal hot electron effects that were discussed as a result, in our opinion, suggests that future conferences should further encourage reports on such device research. On behalf of the Program and International Advisory Committees, we thank the participants, who made the conference a successful and pleasant experience, and the support of the Army Research Office, the Office of Naval Research, and the Beckman Institute of the University of Illinois at Urbana-Champaign. We are also indebted to Mrs. Sara Starkey and Mrs.
