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

Journal of Applied Physics

V. A. Shalygin, M. D. Moldavskaya, M. Ya. Vinnichenko, K. V. Maremyanin, A. A. Artemyev, V. Yu. Panevin, L. E. Vorobjev, D. A. Firsov,  V. V. Korotyeyev, A. V. Sakharov, E. E. Zavarin, D. S. Arteev, W. V. Lundin, A. F. Tsatsulnikov, S. Suihkonen,   C. Kauppinen

Simulated transmittance (a) and absorptivity (b) spectra of the structures with different grating geometries for the radiation with p$p$-polarization. Thin solid lines represent the results of simulation for ideal monochromatic radiation for the grating period a=1000$a=1000$ nm, and metal stripe width w=500$w=500$ nm. Thick solid lines show the results of the averaging of the thin curves with respect to a period of Fabry–Pérot oscillations. Dashed lines represent the simulation results after the spectral averaging for the 800-nm-period grating with w=400$w=400$ nm. Arrow in the inset in panel (a) shows the direction of the electric field oscillations for p$p$-polarized radiation (in respect to the metal strips of the grating). Inset in panel (b) demonstrates a cross section of the structure.

https://aip.scitation.org/doi/10.1063/1.5118771

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$I$–V$V$ 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.