Author: Fedor T. Vasko Publisher: Springer Science & Business Media ISBN: 1461205352 Category : Technology & Engineering Languages : en Pages : 402
Book Description
The theoretical basis and the relevant experimental knowledge underlying our present understanding of the electrical and optical properties of semiconductor heterostructures. Although such structures have been known since the 1940s, it was only in the 1980s that they moved to the forefront of research. The resulting structures have remarkable properties not shared by bulk materials. The text begins with a description of the electronic properties of various types of heterostructures, including discussions of complex band-structure effects, localised states, tunnelling phenomena, and excitonic states. The focus of the remainder of the book is on optical properties, including intraband absorption, luminescence and recombination, Raman scattering, subband optical transitions, nonlinear effects, and ultrafast optical phenomena. The concluding chapter presents an overview of some of the applications that make use of the physics discussed. Appendices provide background information on band structure theory, kinetic theory, electromagnetic modes, and Coulomb effects.
Author: Lok C. Lew Yan Voon Publisher: Universal-Publishers ISBN: 0965856445 Category : Science Languages : en Pages : 263
Book Description
This study is a theoretical investigation of the electronic and optical properties of intrinsic semiconductors using the orthogonal empirical tight binding model. An analysis of the bulk properties of semiconductors with the zincblende, diamond and rocksalt structures has been carried out. We have extended the work of others to higher order in the interaction integrals and derived new parameter sets for certain semiconductors which better fit the experimental data over the Brillouin zone. The Hamiltonian of the heterostructures is built up layer by layer from the parameters of the bulk constituents. The second part of this work examines a number of applications of the theory. We present a new microscopic derivation of the intervalley deformation potentials within the tight binding representation and computes a number of conduction-band deformation potentials of bulk semiconductors. We have also studied the electronic states in heterostructures and have shown theoretically the possibility of having barrier localization of above-barrier states in a multivalley heterostructure using a multiband calculation. Another result is the proposal for a new "type-II" lasing mechanism in short-period GaAs/AlAs superlattices. As for our work on the optical properties, a new formalism, based on the generalized Feynman-Hellmann theorem, for computing interband optical matrix elements has been obtained and has been used to compute the linear and second-order nonlinear optical properties of a number of bulk semiconductors and semiconductor heterostructures. In agreement with the one-band elective mass calculations of other groups, our more elaborate calculations show that the intersubband oscillator strengths of quantum wells can be greatly enhanced over the bulk interband values.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
During the last decades, semiconductors have become increasingly important for many technological applications due to their intriguing electronic properties. As an example, the conductivity of a semiconductors rises with increasing temperature which is opposite to the observations in metals. It is possible to modify the conductivity by the selective introduction of impurities. This so called doping allows for designing devices with well defined conduction properties like for example diodes or transistors. The invention of latter ones has been an important step in the development of modern computers. Unfortunately, the same physical processes that allow to design the electronic characteristics make semiconductor properties very sensitive to undesired impurities such that Wolfgang Pauli called semiconductor physics "dirt physics" in the 1920s. Today, modern epitaxy techniques allow to grow high-quality semiconductor devices with growth accuracies of one single atomic monolayer and a minimum of impurities. The origin of the interesting electronic properties of semiconductors is their special band structure. In contrast to conductors and similar to insulators, semiconductors have a filled valence band and an empty conduction band in the ground state. These bands are energetically separated by the band-gap energy. Compared to insulators, the band-gap energy is small (on the order of 1 eV) such that electrons can be excited from the valence band to the conduction band. The missing electrons in the valence band are often called holes and treated like quasi-particles that have opposite charge, spin and free-particle mass compared to the excited electrons. Depending on the structure of the semiconductor device and the environmental conditions, the electrons in the conduction band may act like the free electrons of a conductor and thus contribute to the conductivity. "Über Halbleiter sollte man nicht arbeiten, das ist eine Schweinerei, wer weiß ob es überhaupt.
Author: Marcin L. Sadowski Publisher: Springer Science & Business Media ISBN: 9401141584 Category : Science Languages : en Pages : 443
Book Description
Optical methods for investigating semiconductors and the theoretical description of optical processes have always been an important part of semiconductor physics. Only the emphasis placed on different materials changes with time. Here, a large number of papers are devoted to quantum dots, presenting the theory, spectroscopic investigation and methods of producing such structures. Another major part of the book reflects the growing interest in diluted semiconductors and II-IV nanosystems in general. There are also discussions of the fascinating field of photonic crystals. `Classical' low dimensional systems, such as GsAs/GaAlAs quantum wells and heterostructures, still make up a significant part of the results presented, and they also serve as model systems for new phenomena. New materials are being sought, and new experimental techniques are coming on stream, in particular the combination of different spectroscopic modalities.
Author: G. Martinez Publisher: Springer Science & Business Media ISBN: 9780792320586 Category : Science Languages : en Pages : 330
Book Description
It is widely recognized that an understanding of the optical pro perties of matter will give a great deal of important information re levant to the fundamental physical properties. This is especially true in semiconductor physics for which, due to the intrinsic low screening of these materials, the optical response is quite rich. Their spectra reflect indeed as well electronic as spin or phonon transitions. This is also in the semiconductor field that artificial structures have been recently developed, showing for the first time specific physical properties related to the low dimentionality of the electronic and vi bronic properties : with this respect the quantum and fractional quan tum Hall effects are among the most well known aspects. The associated reduced screening is also a clear manifestation of these aspects and as such favors new optical properties or at least significantly enhan ces some of them. For all these reasons, it appeared necessary to try to review in a global way what the optical investigation has brought today about the understanding of the physics of semiconductors. This volume collects the papers presented at the NATO Advanced study Inst i tut e on "Optical Properties of Semiconductors" held at the Ettore Majorana Centre, Erice, Sicily on March 9th to 20th, 1992. This school brought together 70 scientists active in research related to optical properties of semiconductors. There were 12 lecturers who pro vided the main contributions .
Author: Fedor T. Vasko
Author: Christoph Schlichenmaier
Author: Saadi Lamari
Author: Lok C. Lew Yan Voon
Author: 
Author: Jiangbo Wang
Author: Sung-Ryul Yang
Author: D. Birkedal
Author: Marcin L. Sadowski
Author: G. Martinez