Electronic Structure And Optical Properties Of Semiconductors

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 .

Examines the optical properties of low-dimensional semiconductor structures, a hot research area - for graduate students and researchers.

This monograph is concerned with the III-V bulk and low-dimensional semiconductors, with the emphasis on the implications of multi-valley bandstructures for the physical mechanisms essential for opto-electronic devices. The optical response of such semiconductor materials is determined by many-body effects such as screening, gap narrowing, Fermi-edge singularity, electron-hole plasma and liquid formation. Consequently, the discussion of these features reflects such interdependencies with the dynamics of excitons and carriers resulting from intervalley coupling.

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.

Optical Properties and Band Structure of Semiconductors, Volume 1 presents the experimental studies of the fundamental energy band structure of semiconductors and insulators. This book provides detailed information of the available measurement methods and results for a large number of both cubic and non-cubic materials. Comprised of 10 chapters, this volume begins with an overview of the fundamental band structure of semiconductors. This text then discusses the instrumentation and methods available for the measurement of absorption coefficient, absolute reflection coefficient, and other optical properties of insulators and semiconductors primarily in their fundamental region. Other chapters consider the interband transitions in the one-electron approximation. The final chapter deals with the equivalence of the transverse and longitudinal dielectric constants in the frequency range under consideration. This book is a valuable resource for solid state physicists. Readers and researchers with interest in the electron and optical properties of semiconductors and insulators will also find this book useful.