Room temperature coherent and voltage tunable terahertz emission from nanometer-sized field effect transistors

Abstract

We report on reflective electro-optic sampling measurements of TeraHertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. We establish that the physical mechanism of the coherent TeraHertz emission is related to the plasma waves driven by simultaneous current and optical excitation. A significant shift of the plasma frequency and the narrowing of the emission with increasing channel's current are observed and explained as due to the increase of the carriers density and drift velocity.T.

Investigation of 2D plasma resonances in HEMTs by using electro-optical sampling technique

“…The threshold voltage V th ≈ 300 meV. The room temperature THz emission measurements were performed using a reflective EOS technique (see [8] for more details). The HEMT was loaded to external source-gate and source-drain circuits which provided constant values of the gate voltage V g and the drain current j d during the pump and probe optical pulses.…”

“…The parameters of the InGaAs HEMT structure were taken similar to those used above and in recent experiments [8].…”

“…The excitation process itself and further temporal evolution of such 2D plasma waves is beyond the scope of these approaches. In our opinion, this deficiency can be covered by using the electro-optical sampling (EOS) measurements of THz radiation emission from FETs/HEMTs induced by the femto-second laser pulse [7][8][9].…”

Terahertz instability of field effect transistor in quantum regime

“…Furthermore, experimental investigations have manifested that the emission of terahertz radiation in nanometer FET at lower temperature was observed. [8][9][10][11][12][13] Indeed, with the rapid progress in nanotechnology, nanostructures such as nanodiodes, nanotriodes, Nano-FET, and nanogaps ranging from sub-10 nm to 100s of nm are readily fabricated. 14,15 In a nanometer scale and at lower temperature, quantum effects such as quantum statistical pressures for electrons, the electron tunneling, and many electron exchange-correlation interaction should become very important.…”

“…We assume the same boundary conditions, as in Ref. 1, which correspond to zero ac potential at the source and zero ac current at the drain n 1 ð0Þ ¼ 0; n 0 v 1 ðLÞ þ v 0 n 1 ðLÞ ¼ 0; (10) where L is the distance between the source and drain contacts. From Eqs.…”