Semiconductor devices are present everywhere in modern society. Understanding them is critical for anyone pursuing a career in areas such as semiconductor processing, electrical circuit design, VLSI design, power engineering, and solid-state sensors. Students with a background in electrical engineering, material science, physics, process engineering, or nanotechnology will all find this book useful. This textbook starts with a description of what a semiconductor is and proceeds to describe how semiconductor devices work. The semiconductor devices covered include the MOSFET, diode, LED, solar cell, power MOSFET, and IGBT. The book focuses on an understanding of the key concepts. This book is written for use in the classroom or for self-study and includes numerous examples that are clearly worked out. The author brings years of teaching experience breaking down complicated topics and making them easy to understand without sacrificing the level of the content.