Gunn or Transferred-Electron Devices and Circuits

Transferred-electron devices are the only microwave devices whose operation is based solely on the bulk-material properties of semiconductors such as GaAs or InP. These devices are employed mainly in low-noise medium-power oscillators up to high millimeter-wave frequencies. James B. Gunn was the first scientist to observe the underlying physical phenomenon in an experiment and, therefore, these devices are often referred to as Gunn devices. This chapter describes the principles of operation, basic fabrication technologies, and common oscillator circuits for them. Different device structures for performance optimization and optimization procedures and simulation tools are discussed. The chapter also summarizes the current state of the art of TEDs, and the outlook covers the prospects of more recent device structures and material systems.