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

Abstract

Propagating between the contacts of a field-effect transistor ͑FET͒, plasma waves in its channel can become unstable and lead to generation of terahertz radiation. While previous studies of this instability concentrated on rectangular FETs, alternative geometries present fresh opportunities. We studied theoretically plasma oscillations in a gated FET with Corbino geometry where, in contrast with the rectangular FET, the oscillations become unstable at symmetric boundary conditions. Moreover, their lowest eigenfrequency is almost twice as high as that in the rectangular FET at comparable instability increments. These advantages make the Corbino FET promising for practical realizations of terahertz oscillators.

Distributed gain in plasmonic reflectors and its use for terahertz generation

“…where A is a constant. We described the electron dynamics using the standard linearized hydrodynamic model [4][5][6][7][8][9][10][11][12] as follows. The total electron density, n tot , and velocity, v tot , have the form…”

“…Various generation mechanisms have been considered theoretically, including, for example, plasmon interactions with quantum-wire gratings [4] or optical phonons [5][6][7], and the Dyakonov-Shur instability [8]. The latter has inspired a number of theoretical [9][10][11][12] and experimental [13][14][15] studies, but the terahertz power attainable was low (see Ref. [16] for a review).…”

Modeling and analysis of a new THz source based on cylindrical FET (C-FET)

“…Prior studies in a Transistor (by using the theory of Dyakonov and Shur) show that a constant drain current, makes the amplitude of plasma waves in the channel of the Transistor, to grow and become constant while the momentum relaxation time damps the amplitude [11][12][13][14]21]. While previous analytical and experimental studies, clearly established the existence of plasma waves in flat-2D systems via a simplified one dimensional hydrodynamic model, there is a lack of resource on the formulation and investigation of this theory on the applicability and generation of THz waves in coaxial transistors.…”

“…In [21] Plasma oscillations and instability has been investigated with Corbino geometry in cylindrical coordinate where the oscillations become unstable at symmetric boundary conditions with frequency in the THz range.…”

Investigation of the Dyakonov-Shur instability for THz plasma waves in quantum gated cylindrical FET

“…[11][12][13][14] On the other hand, some scientists have noted the DS instability in different transistors, such as negative differential conductance gate transistors, ungated rectangle FETs, corbino geometry FETs, and cylindrical FETs. [15][16][17][18][19][20][21] In recent years, with the development of nanoscience, nanometer FETs (quantum FETs) have been manufactured and can be used to reduce the size of the circuit system. In the heterojunction of nanometer FETs, the de Broglie wavelength is similar to or larger than the distance of electrons, and the electron state changes from the Maxwell-Boltzmann distribution to Fermi-Dirac distribution at Fermi temperature.…”