Plasma oscillations and terahertz instability in field-effect transistors with Corbino geometry

摘要

Propagating between the contacts of a field-effect transistor u0002FETu0003, plasma waves in its channel cannbecome unstable and lead to generation of terahertz radiation. While previous studies of thisninstability concentrated on rectangular FETs, alternative geometries present fresh opportunities. Wenstudied theoretically plasma oscillations in a gated FET with Corbino geometry where, in contrastnwith the rectangular FET, the oscillations become unstable at symmetric boundary conditions.nMoreover, their lowest eigenfrequency is almost twice as high as that in the rectangular FET atncomparable instability increments. These advantages make the Corbino FET promising for practicalnrealizations of terahertz oscillators. © 2010 American Institute of Physics. u0004doi:10.1063/1.3532850