Plasmon recombination in narrowgap HgTe quantum wells

Abstract

The dispersion laws of two-dimensional plasmons in narrow-gap HgTe/CdHgTe quantum wells are calculated taking into account the spatial dispersion of the electron susceptibility. At the energy scale of the band gap the dependence of plasmon frequencies on the wave vector is shown to be close to linear that changes significantly the critical concentration of noneqilibrium electron-hole gas corresponding to ‘switching-on’ the carrier recombination with plasmon emission. The recombination rates with the plasmon emission have been calculated. The ‘plasmon’ recombination is shown to dominate at the carrier concentration over (1.2–2) 1011 cm−2 in a 5-nm-wide HgTe quantum well (band gap of 35 meV) that makes plasmon generation (spasing) in THz frequency range feasible.

Оптимизация диэлектрического волновода для лазерных структур дальнего инфракрасного диапазона на основе HgTe/CdHgTe

“…лизуемой в " длинноволновых" КЯ HgTe/HgCdTe при разумных мощностях накачки. Так, при меньших концентрациях носителей в КЯ HgTe/HgCdTe преобладающим процессом межзонной рекомбинации является оже-рекомбинация [17]. Характерные времена этого процесса -субнаносекундные, τ ≈ 0.5 нс при N th ≈ 5 • 10 10 см −2 и ∼ 0.1 нс при N max ≈ 2 • 10 11 см −2 .…”

“…Характерные времена этого процесса -субнаносекундные, τ ≈ 0.5 нс при N th ≈ 5 • 10 10 см −2 и ∼ 0.1 нс при N max ≈ 2 • 10 11 см −2 . При превышении величины N max пороговым образом включается сверхбыстрый процесс межзонной рекомбинации (времена ∼ 1 пс), сопровождающийся генерацией двумерных плазмонов [17]. За счет этого процесса мощность накачки, необходимая для достижения схожей концентрации носителей, возрастает на 2 порядка величины.…”

Two-Dimensional Plasmons in Laterally Confined 2D Electron Systems

“…Due to the rather low 2D carrier concentration and the simultaneous high quality of modern 2DESs, 2D plasmon frequencies may lie in giga- and terahertz ranges, which are very attractive for applications. The plasmons can be used for generators and detectors of terahertz radiation [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ], they limit the operational range of a number of devices [ 18 ], and are also interesting for their fundamental properties [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ].…”

Plasmon gain in HgTe/CdHgTe multi-quantum-well heterostructures

“…It should be noted that the concentrations of nonequilibrium charge carriers in QWs of a multi-quantum-well (MQW) structure are approximately the same in the case of intrawell absorption of exciting radiation. In contrast to graphene, the lifetime of nonequilibrium charge carriers in this material is several orders of magnitude longer [7,8], which facilitates the creation of the inverse band population required for plasmon generation. In addition to the possibility of controlling the band structure, the technology for producing QWs from this material is much better developed than the technology for producing graphene.…”