Bulk negative-resistance semiconductor devices

Recent research on semiconductors that exhibit bulk negative resistivity has led to new devices for pulse regeneration, logic function generation, amplification, and millimeter-wave power generation. These are bulk devices in the sense that ac gain is derived from the bulk negative-resistance property of certain uniform semiconductors, rather than from the properties of junctions between different types of semiconductors. Bulk devices are capable of operating with more power at higher speeds and frequencies than conventional junction devices such as transistors.