Ansgar Jüngel Livres

Semiconductor devices are ubiquitous in the modern computer and telecommunications industry. A precise knowledge of the transport equations for electron flow in semiconductors when a voltage is applied is therefore of paramount importance for further technological breakthroughs. In the present work, the author tackles their derivation in a systematic and rigorous way, depending on certain key parameters such as the number of free electrons in the device, the mean free path of the carriers, the device dimensions and the ambient temperature. Accordingly a hierarchy of models is examined which is reflected in the structure of the book: first the microscopic and macroscopic semi-classical approaches followed by their quantum-mechanical counterparts.

The papers in this book originate from lectures which were held at the "Vienna Workshop on Nonlinear Models and Analysis" – May 20–24, 2002. They represent a cross-section of the research field Applied Nonlinear Analysis with emphasis on free boundaries, fully nonlinear partial differential equations, variational methods, quasilinear partial differential equations and nonlinear kinetic models.

In this book a hierarchy of macroscopic models for semiconductor devices is presented. Three classes of models are studied in detail: isentropic drift-diffusion equations, energy-transport models, and quantum hydrodynamic equations. The derivation of each of the models is shown, including physical discussions. Furthermore, the corresponding mathematical problems are analyzed, using modern techniques for nonlinear partial differential equations. The equations are discretized employing mixed finite-element methods. Also, numerical simulations for modern semiconductor devices are performed, showing the particular features of the models. Modern analytical techniques have been used and further developed, such as positive solution methods, local energy methods for free-boundary problems and entropy methods. The book is aimed at applied mathematicians and physicists interested in mathematics, as well as graduate and postdoc students and researchers in these fields.

Ein unentbehrlicher Begleiter für die Grundvorlesung in Mathematik, der während des gesamten Chemiestudiums gute Dienste bei allen mathematischen Fragen und Problemen leistet. In bewährter Weise wird auch in der 8. Auflage das notwendige mathematische Rüstzeug für das Chemiestudium in leicht verständlicher Form vermittelt. Viele anschauliche Beispiele aus der Chemie stellen den Bezug zur fachlichen Anwendung her. Übungsaufgaben zu jedem Unterkapitel - mit Lösungen im Anhang - ermöglichen es, das erworbene Wissen selbstständig zu überprüfen. Die 8. Auflage wurde um neue Abschnitte zu den Grundlagen der Dichtefunktionaltheorie und zum maschinellen Lernen ergänzt; Letzteres spielt eine immer größere Rolle beim Einsatz von Expertensystemen bzw. von künstlicher Intelligenz für die Analyse und Vorhersage von chemischen Reaktionen und Strukturen.