Almost every aspect of modern life is affected by a practical result of research in condensed matter physics: semiconductor devices. The performance of these solid-state devices is determined largely by the physical properties of the interfaces within them. It is the properties of interfaces in rectifying metal-semiconductor junctions, ohmic contacts, metal-oxide-semiconductor structures and p-n junctions, for example, that determine the performance of such devices as infrared detectors, microwave amplifiers, computer processors and laser diodes, respectively.