U.S.-Austria Cooperative Research: Electronic Properties of Semiconductor Systems of Reduced Dimensionality (Materials Research)

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This award will support a three-year cooperative research project in solid state physics between Professor Bruce D. McCombe, Department of Physics and Astronomy, State University of New York at Buffalo, and Prof. Dr. Friedemar Kuchar, Institute of Solid State Physics, University of Vienna, Austria. The objectives of the joint study are (1) to improve present understanding of the "insulator"-semiconductor interface in indium-based III-V compounds (InSb, InAs, InP) and to develop new or improved insulators and metal-insulator-semiconductor (MIS) structures in the process and (2) to increase understanding of the basic physics and unique properties of the nearly two-dimensional electron gas, particularly the Quantum Hall Effect, in several semiconductor structures. Samples will be obtained from a variety of sources, including in-house fabrication by organometallic chemical vapor deposition. A large range of characterization techniques will be used to study the interfaces and fabrication techniques. The basic physics of the nearly 2-dimensional gas in these structures will be investigated by several experimental methods. Basic physical phenomena to be examined are: electron-electron interactions, electron-phonon interaction, localization effects in the Quantum Hall Effect regime, and spin-orbit coupling in narrow gap/reduced dimensionality systems. Use of Transmission Electron Microscopy will permit correlation of the electrical properties of the samples with the microscopic physical structure at the interfaces, important in efforts to make better interfaces. This project is directed at improving basic understanding of semiconductor device structures, whose operation depends on confining the motion of electrons in one direction, so that for many purposes the electrons behave as a two-dimensional (rather than three-dimensional) gas. The cooperating scientists have considerable experience in studying such systems of "reduced dimensionality." There is current interest in these systems from both technological and scientific points of view. The joint study would thus have an impact both in the areas of electronics technology and in basic physics. In spite of considerable work done over the past decade, a detailed microscopic understanding of the interface electronic properties of the structures to be examined here and the variety of physical phenomena associated with the nearly two-dimensional electron gas that can be produced within them has not emerged. The U.S. and Austrian research groups bring different facilities and techniques to the project, thereby allowing a much more complete range of investigations to be carried out than could be conducted by either group working alone. The investigators believe that their dual technology/physics approach, coupled with the wide range of samples, characterization techniques, and expertise available through the collaboration, enhances the opportunity for substantial progress in both areas. This award will support the transportation and overseas subsistence expenses of Professor McCombe, as well as some shipping costs. The Austrian Science Foundation (FWF) is providing counterpart support to Professor Kuchar. This project takes place under the U.S.-Austria Cooperative Science Program.