Semiconductor Physics

Semiconductors are materials which have a conductivity between conductors (generally metals) and nonconductors or insulators. Semiconductors can be pure elements, such as silicon or germanium, or compounds such as gallium arsenide or cadmium selenide. Semiconductor devices are all around us. They can be found in just about every commercial product we touch, from the family car to the pocket calculator. Semiconductor devices are contained in television sets, portable radios, stereo equipment, and much more. Science and industry also rely heavily on semiconductor devices. Research laboratories use these devices in all sorts of electronic instruments to perform tests, measurements, and numerous other experimental tasks. Industrial control systems (such as those used to manufacture automobiles) and automatic telephone exchanges also use semiconductors. Even today heavy-duty versions of the solid-state recti er diode are being use to convert large amounts of power for electric railroads. Of the many di erent applications for solid-state devices, space systems, computers, and data processing equipment are some of the largest consumers.