This book, now in its Second Edition, provides a basis for understanding the characteristics, working principle, operation and limitations of semi-conductor devices. In this new edition, many sections are re-written to present the concepts related to device physics in more clearer and easy to understand manner. The primary objective of this textbook is to provide all the relevant topics on the semiconductor materials and semiconductor devices in a single volume. It includes enough mathematical expressions to provide a good foundation for the basic understanding of the semiconductor devices. It covers not only the state-of-the-art devices but also future approaches that go beyond the current technology. Designed primarily as a text for the postgraduate students of physics and electronics, the book would also be useful for the undergraduate students of electronics and electrical engineering, and electronics and communi-cation engineering. Highlights of the Book : Includes topics on the latest technologies Covers important points in each chapter Provides a number of solved and unsolved problems along with explanation type questions Emphasizes on the mathematical derivation