Selective terahertz emission due to electrically excited 2D plasmons in AlGaN/GaN heterostructure

Abstract

Terahertz radiation emission from an electrically excited AlGaN/GaN heterostructure with a surface metal grating was studied under conditions of two-dimensional (2D) electron heating by the lateral electric field. Intensive peaks related to nonequilibrium 2D plasmons were revealed in the terahertz emission spectra with up to 4 times selective amplification of the radiation emission in the vicinity of 2D plasmon resonance. This selective emission was shown to be frequency-controllable by the grating period. Exact spectral positions of the 2D plasmon resonances were preliminarily experimentally detected with the help of equilibrium transmission spectra measured at various temperatures. The resonance positions are in a satisfactory agreement with the results of theoretical simulation of the transmission spectra performed using a rigorous solution of Maxwell's equations. The effective temperature of hot 2D electrons was determined by means of I-V characteristics and their analysis using the power balance equation. It was shown that for a given electric field, the effective temperature of nonequilibrium 2D plasmons is close to the hot 2D electron temperature. The work may have applications in GaN-based electrically pumped emitters of terahertz radiation.

Room-Temperature Amplification of Terahertz Radiation by Grating-Gate Graphene Structures

“…Nevertheless, despite tremendous efforts, neither the room-temperature resonant detection nor the currentstimulated emission or amplification of THz radiation have been observed so far (see the discussion in the recent work of Ref. [23], where low-temperature THz emission is discussed).…”

Radiation thermal effect of a fire spilling fuel-air mixtures on a person

“…This article discusses the situation when a person, being at some distance from the center of the diameter of the oil spill, during his sudden outbreak, for some time (about 3-5 s) remains in shock (determined by the reaction time to the outbreak, turn, start of running), then begins to run away in the direction of decreasing the heat flux intensity to a safe distance determined by the intensity of the acting heat flux of 1.4 kW/m2 [21][22][23][24][25]. However, during the movement of a person to the border of the safe zone, the effect of thermal radiation continues on him.…”

Terahertz Spectroscopy of Thermal Radiation from AlGaN/GaN Heterostructure on Sapphire at Low Temperatures

“…However, at sample temperatures below 155 K the thermal radiation is weak and electroluminescence is caused by another radiative mechanisms. We measure directly, that thermal radiation from the sample contributes to the THz spectrum of the electroluminescence at much higher average electrical power than indicated in the [8] measuring hot-electron temperature and electron plasma radiation.…”

“…Field-effect transistors (FETs) can operate as a compact detector [2][3][4] or emitter [5][6][7] for THz waves, when incoming radiation creates voltage between transistor channel terminals, or the opposite case where voltage applied along the channel excites THz radiation. For example, resonant THz emission of tunable frequency from 2DEG plasma oscillations can be excited by the strong electric field along HEMT channel [8], while its frequency could be controlled by a gate bias. In this light, GaN, which is suitable for high-power electronics, is a promising material.…”

“…Therefore, the investigation, which would help to find the way to manage the unwanted THz signal, is very important. It was shown recently that 450 V/cm electric field pulses of only 8 µs in duration can elevate the temperature of AlGaN/GaN heterostructure lattice significantly even if the sample is in liquid helium [8]. On the other hand, THz electroluminescence from shallow impurities invoked by a strong electric field can interplay with thermal radiation.…”