In the series of International Winter Schools on New Developments in Solid State Physics, the fourth one was devoted to the subject: "Two- Dimensional Systems: Physics and Devices". For the second time the pro- ceedings of one of these Winter Schools appear as a volume in the Springer Series in Solid-State Sciences (the earlier proceedings were published as Vol. 53). The school was held in the castle of MauterndorfjSalzburg (Austria) February 24-28, 1986. These proceedings contain contributions ba:sed on the thirty invited lectures. The school was attended by 179 registered participants (40% students), who came from western European countries, the United States of America, Japan, the People's Republic of China and Poland. As far as the subjects are conterned, several papers deal with the growth and characterization of heterostructures. Dynamical RHEED tech- niques are described as a tool for in situ studies of MBE growth mech- anisms. Various growth techniques, including MBE, MOMBE, MOCVD and modifications of these, are discussed. The limiting fa.ctors for the carrier mobilities and the inftuence of the spacer thickness in single het- erostructures of GaAs/GaAIAs seem to be understood and are no longer a matter of controversy. In addition, the growth of two fascinating systems, Si/SiGe and Hg _ Cd Te/CdTe, is discussed in detail.

The winter school on Localization and Confinement of Electrons in Semicon ductors was the sixth of a series dealing with new developments in solid state physics organized by the Austrian Physical Society. The school, which was held in the castle of Mautemdorf, in the federal province of Salzburg, Austria, February 19-23, 1990, was attended by about 200 participants. This is the fourth such winter school to have the proceedings published in the Springer Series in Solid-State Sciences, the earlier ones appearing as Vols. 53, 67 and 83. The contributions of the invited speakers are arranged in seven parts according to topic: quantum boxes and quantum wires; localization and the metal-insulator transition; the integer and fractional quantum Hall effects and electron-electron interactions; tunneling and localization in low-dimensional structures and superlattices; optical properties of confined systems; impurities in quantum well structures; and optical and magnetic properties of dilute mag netic semiconductor quantum well. structures. A particular intention of this book is to present relevant introductory articles alongside the most recent research reports, all written by experts in the fields of localization and condensation of electrons in semiconductors, the quantum Hall effect, lateral superlattices, ballistic transport, etc. The fascinating subject of quantum boxes (dots) and quantum wires is treated in considerable detail. Experimental techniques for producing later ally structured two-dimensional electron gas systems are described together with methods for studying their electrical and optical properties."

Owing to new physical, technological, and device concepts of low-dimensionalelectronic systems, the physics and fabrication of quasi-zero, one- and two-dimensional systems are rapidly growing fields. The contributions presented in this volume cover results of nanostructure fabrication including recently developed techniques, for example, tunneling probe techniques and molecular beam epitaxy, quantum transport including the integer and fractional quantum Hall effect, optical and transport studies of the two-dimensional Wigner solid, phonon studies of low-dimensional systems, and Si/SiGe heterostructures and superlattices. To the readers new in the field this volume gives a comprehensive introduction and for the experts it is an update of their knowledge and a great help for decisions about future research activities.

This volume presents a discussion of the latest results in the physics of low-dimensional structures. At the winter school major breakthroughs were reported, and some of the excitement of the participants is reflected in the contributions. The topics treated range from the fabrication of microstructures and the physical background of future semiconductor devices to vertical transport in nanostructures, universal conductance fluctuations, and the transition from two-dimensional to one-dimensional conduction in semiconductor structures.