The Proceedings of the 17th International Conference on the Physics of Semiconductors are contained in this volume. A record 1050 scientists from 40 countries participated in the Conference which was held in San Francisco August 6·1 0, 1984. The Conference was organized by the ICPS Committee and sponsored by the International Union of Pure and Applied Physics and other professional, government, and industrial organizations listed on the following pages. Papers representing progress in all aspects of semiconductor physics were presented. Far more abstracts (765) than could be presented in a five-day meeting were considered by the International Program Committee. A total of 350 papers, consisting of 5 plenary, 35 invited, and 310 contributed, were presented at the Conference in either oral or poster sessions. All but a few of the papers were submitted and have been included in these Proceedings. An interesting shift in subject matter, in comparison with earlier Conferences, is manifested by the large number of papers on surfaces, interfaces, and quantum wells. To facilitate the use of the Proceedings in finding closely related papers among the sometimes relatively large number of contributions within a main subject area, we chose not to arrange the papers strictly according to the Conference schedule. We have organized the book, as can be seen from the Contents, into specific subcategories and subdivisions within each major category. Plenary and invited papers have been placed together with the appropriate contributed papers.

This volume contains contributions presented at the 12th International Conference on High Magnetic Fields in Semiconductor Physics. In order to give an overview, 37 lecturers not only reviewed the latest results in their field, but also gave a general introduction. The rapid development of semiconductor physics and technology during the last few years has resulted in an extensive application of high magnetic fields in both fundamental and applied research; more than 160 contributed papers were presented as posters.Sixteen years after its discovery, the quantum Hall effect (QHE) is still a subject of high activity. Many new results on the fractional QHE were presented; in addition to 6 invited papers, there were 43 contributions. Another field of high activity is magneto-optics, and 49 posters were presented. Magnetotransport also turned out to be of high interest, and magnetic semiconductors played a prominent role at the conference, too.Without doubt, the availability of superconducting magnets in most laboratories contributed to the growth of semiconductor physics in high magnetic fields. Because not all experiments can be performed in fields up to 10 or 15 teslas, high magnetic field laboratories offering larger fields are indispensable. There were reports from four laboratories on present work going on at these installations.

The Twelfth International Conference on the Physics of Semiconductors was held at Stuttgart, Federal Republic of Germany, from July 15 to 19, 1974. The Conference was sponsored by the International Union of Pure and Applied Physics and we wish to thank this Organization as well as all the other Institutions and Companies listed on the preceding page for their substantial support. About 700 scientists from 31 countries came to Stuttgart in order to attend the Conference. Following the example of the previous Conference at Warsaw, a distinction was made between plenary invited and invited papers presented at parallel sessions. Altogether, the Proceedings contains 27 invited and 206 contributed papers. The members of the International Program Committee had the difficult task of making a selection from 550 abstracts. Their work was essential for the success of the Conference and it is gratefully acknow­ ledged. The number of pages alloted to each paper had to be limited in order to keep the Proceedings within reasonable size. In general, the papers in the Proceedings have been arranged according to the Conference Program except for the following changes: Each plenary invited paper was associated with an appropriate session, the sessions were put into a slightly different order and, in a few cases, new titles were introduced.

Ferroelectric materials, in addition to possessing the unique property of a reversible, spontaneous polarization, exhibit a range of other significant and useful properties. These include high values of piezoelectric, pyroelectric, nonlinear optic, electrooptic, photorefractice and dielectric permittivity coefficients. Another fascinating property of ferroelectric materials is their photovoltaic effect. Photovoltaic effects have been extensively studied in the past in symmetric materials such as silicon. This volume is the first concentrated treatment of the characteristics, theory and potential applications of the photovoltaic effect in noncentrosymmetric materials, which include ferroelectrics and piezoelectrics. The book also deals with the relationship between the photovoltaic and the photorefractive effects. The latter has already been well-studied and is finding many applications in optical processing and computing. This volume should prove to be an important text as well as a comprehensive reference source for basic and applied researchers working on photovoltaic, photorefractive and other photoeffects in ferroelectrics and related materials.

This fourth volume in the series 'Physics and Chemistry of Materials with Layered Structures' is concerned with providing a critical review of the significant optical and electrical properties by established authors who have themselves made many significant contributions to these fields. Research into these materials has recently gained a new impetus and their fascinating properties have attracted many new research workers. These people should find much of value in the reviews contained in this volume and the editor is very much indebted for the painstaking and hard work put into the preparation of the various chapters by the authors. The optical properties provide useful information for deriving the band struc tures, a knowledge of which is required for an interpretation of measurements on the electronic properties. The chapters by Dr Evans, Dr Williams and Dr Bordas describe different techniques which have provided much detailed data on this subject. An interesting property of these materials is the comparative ease with which thin specimens may be prepared for these measurements and this is highlighted in the super conducting experiments outlined by Professor Frindt and Dr Huntley. These authors together with Dr Vandenberg's chapter on the magnetic properties also describe the interesting and significant intercalation mechanisms whereby a wide range of organic compounds and alkali metals may be incorporated in the lattice. This provides an additional parameter for varying the properties of these materials and may yet be seen to provide eventual possible applications of layer compounds.

This text offers basic understanding of the electronic structure of covalent and ionic solids, simple metals, transition metals and their compounds; also explains how to calculate dielectric, conducting, bonding properties.