Nanoscale physics

Effect of interface phonons on the functioning of quantum cascade detectors operating in far infrared range
Seti Ju.O., Tkach M.V., Vereshko E.Ju., Voitsekhivska O.M.
Department of Theoretical Physics and Computer Simulation, Yuriy Fedkovych Chernivtsi National University, 2, Kotsyubinsky Str., 58012, Chernivtsi, Ukraine,
E-mail: vereshko.yevheniia@chnu.edu.ua
It is well known [1,2], that thanks to the high sensitivity and small noise characteristics, the quantum cascade detectors operating in far infrared range can be potentially used in space investigation, medicine, imaging devices, navigation, environment monitoring, etc. To satisfy practical demands, nano detectors must have rather wide spectral bands, that can be reached by use of two-well active region [3].
Modern quantum cascade detectors can operate at temperatures higher than the room one [1-3], since, the electron-phonon interaction plays not only positive role, being the canal of electron energy relax, but negative too, as a factor causing the renormalizing of their spectral absorption band. Analysis of experimental and theoretical papers shows that investigating the properties of quantum cascade detectors, the golden Fermi rule was usually used for the study of interaction between electrons and confined optical phonons. However, the influence of interface optical phonons was not observed, in spite of their effect can be essential in multi-layered cascades.
In this paper, using the model of position-dependent effective mass and rectangular potentials for the electrons and dielectric continuum model for the interface optical phonons within the method of temperature Green’s functions, the electron energy levels renormalized due to interaction with interface phonons are investigated in the separate cascade of quantum cascade detector operating in far infrared range. The effect of different mechanisms of electron-phonon interaction on the spectral parameters of electron states and absorption band of quantum cascade detector is studied.
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2.	M Beeler et al. III-nitride semiconductors for intersubband optoelectronics: a review // Semicond. Sci. Technol. – 2013. –28. –074022.
3.	Li Liang et al. Long wavelength infrared quantum cascade detector with a broadband response // J. Phys. D: Appl. Phys. – 2018. – 51. – 37LTO1.