Interaction of surface plasmon polaritons in heavily doped GaN microstructures with terahertz radiation

Abstract

We present the results of experimental and theoretical studies of the surface plasmon polariton excitations in heavily doped GaN epitaxial layers. Reflection and emission of radiation in the frequency range of 2-20 THz including the Reststrahlen band were investigated for samples with grating etched on the sample surface, as well as for samples with flat surface. The reflectivity spectrum for p-polarized radiation measured for the sample with the surface-relief grating demonstrates a set of resonances associated with excitations of different surface plasmon polariton modes. Spectral peculiarities due to the diffraction effect have been also revealed. The characteristic features of the reflectivity spectrum, namely, frequencies, amplitudes, and widths of the resonance dips, are well described theoretically by a modified technique of rigorous coupled-wave analysis of Maxwell equations. The emissivity spectra of the samples were measured under epilayer temperature modulation by pulsed electric field. The emissivity spectrum of the sample with surface-relief grating shows emission peaks in the frequency ranges corresponding to the decay of the surface plasmon polariton modes. Theoretical analysis based on the blackbody-like radiation theory well describes the main peculiarities of the observed THz emission. V

Electron heating in GaN/AlGaN quantum well in a longitudinal electric field

“…Terahertz emission of nonequilibrium (hot) two-dimensional (2D) electrons was discovered in a GaN/AlGaN quantum well (QW) [3]. Terahertz radiation related to surface plasmon polaritons was studied in heavily doped n-GaN [4]. THz radiation associated with 2D plasmons was studied in GaN/AlGaN quantum wells [5,6].…”

Modified rigorous coupled-wave analysis for grating-based plasmonic structures with delta-thin conductive channel. Far- and near-field study

“…Recently, great attention has been paid to exploitation of the subwavelength metasurfaced structures in THz and Far-infrared spectral ranges. Particularly, the semiconductor structures with surface-relief gratings [5,6], quantum well (QW) heterostructures [7,8] or graphenebased structures [9] incorporated with metallic gratings are widely discussed as potential efficient emitters and detectors of the THz radiation [10]. In such structures, the gratings play a role of the coupler, facilitating the resonant interaction between incident electromagnetic (em) waves and charge density waves such as surface plasmonpolaritons or 2D plasmons.…”

Nanoscale ballistic diodes made of polar materials for amplification and generation of radiation in the 10 THz-range

“…Note, for semiconductor materials and heterostructures widely used in high speed electronics, the characteristic frequencies of optical phonons vary in a wide THz range. In III-V compounds ω LO are in the range 5 THz (InSb) to 12 THz (GaP) 13 ; for the group-III-nitrides ω LO are of 18 to 22 THz 11,12 , etc. Currently, for this frequency range the physical effects are actively studied, [14][15][16][17][18] as well as their device applications.…”