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Journal of Physical Studies 20(1/2), Article 1703 [6 pages] (2016)
DOI: https://doi.org/10.30970/jps.20.1703 TWO MODELS FOR THE CASCADE OF QUANTUM CASCADE DETECTOR OPERATING IN THE NEAR INFRA-RED RANGEJu. O. Seti, M. V. Tkach, M. V. Pan'kiv
Fedkovych Chernivtsi National University, |
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The local field approach and kinetic equation method is applied to calculate the line broadening of the surface plasmon resonance (SPR) in a spheroidal metal nanoparticle (MN) embedded in any dielectric media. Usually, both the surface and the radiative damping mechanisms play an important role in the plasmon decay. In the MNs of a smaller radii, the penetration depth of the plasmon field reduces and becomes more localized near the surface. As a result, the bulk-induced loss processes play only a minor role and the electronic excitations generated by the surface potential dominate.
Using the analytical and computer calculations for the internal electric field caused by the spontaneous and piezoelectric polarizations the potential profile for the electrons in multilayered resonant tunneling nano-system with semiconductor nitride anisotropic media that have a wurtzite structure and are a cascade of the quantum cascade detector of near infra-red range is obtained. It is established that the internal electric field essentially deforms the electronic potential profile and hence it is to be taken into account for the adequate understanding of physical properties of nitride multilayered resonant tunneling structures being the operating elements of nano-devices.
The analysis of electronic potential profile, energy spectrum, wave functions and oscillator strengths of quantum transitions between the electron states in the separate five-well cascade of quantum cascade detector operating in the near infra-red range (1.55\,мкм) revealed the ambiguous mechanisms of nano-device operations determined by the existence of the ``tattered energetic phonon ladder'' in the extractor. In order to improve the effective operation of the quantum cascade detector, the optimal geometrical design of its cascades is proposed within the increased number of extractor potential wells from four to eight. At such geometrical design of cascades, the electron states in the extractor create a ``complete phonon ladder'' that would provide the radiationless relaxation of electron energy between the excited and ground operating states of neighbor cascades of the quantum cascade detector when the electrons scatter at the high- and low-frequency optical phonons. One can expect that the proposed optimization of a geometrical design of cascades of the quantum cascade detector in the near infra-red range would increase its effective operation.
PACS number(s): 73.21.Fg, 72.80.Ey, 73.63.Hs, 77.22.Ej, 77.65.Bn