The rapidly developing field of electronics is now dominated by devices which are operationally dependent on the physical properties of semiconductors. This clear and comprehensive text explains the effects employed in each class of device and derives formulae that describe the measurable voltages and currents. The revised and updated fourth edition includes new material on the devices used for optical fiber communication, on the new semiconductor alloys (3-5 compounds), and on the properties of multiple thin layers of semiconductors. The treatment of MOS devices is brought into line with that used in the SPICE circuit simulation techniques. Fully illustrated, the book emphasizes diagrams rather than complicated analytical methods and is highly accessible for those in physics and engineering who need an understanding of this subject.