HgCdTe-based quantum-well-heterostructures for mid-infrared heterodyne spectroscopy
Final Report Abstract
The project was focused on the experimental investigation of potential of HgCdTe-based multiquantum-well heterostructures for applications in mid-infrared heterodyne spectroscopy. The studies were seriously affected by the international situation (COVID pandemic, war in Ukraine), which was not been foreseen in advance. As a result, the full program has not been performed at the scale planned in the original proposal, in particular, because the cooperation with the Russian partner had to be suspended. A contingency plan of actions has to be implemented in order to overcome the problems. This allowed to achieve several important findings. The main results achieved in the frame of the project are: 1. Theoretical designs of the dedicated HgTe/Cd1-xHgxTe multiple quantum well heterostructures have been experimentally proved to provide adequate description of the energy spectra, including the designed bandgaps as well as spectra of Hg vacancies, the latter – with a critical reduction of the energy levels due to the limited number of the observed in the analytical spectroscopy intracenter transitions. 2. The investigations of dynamics of induced by infrared ultrafast resonant excitation charge carriers in the available in the frame of the project HgTe/Cd1-xHgxTe multiple quantum well heterostructures, selected the optical excitation mechanisms which could serve for broad-band heterodyne operation, namely those utilizing the intraband relaxation if focusing on the undoped heterostructures. The interband relaxation, having significantly larger oscillator strengths, appear to be a relatively slow process, very likely two orders of magnitude slower if compared to interband decay. This rate could be however, increased (due theoretical predictions), in the doped heterostructures due to the recombination via impurity levels in the material bandgap. 3. Mid-infrared quantum cascade lasers, based on InAs/AlSb quantum wells, have been proven as promising candidates to serve as local oscillators for heterodyne spectroscopy goals in the studied wavelength range, namely at around 17 µm.
Publications
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Recombination in gapless HgTe/CdHgTe quantum well heterostructure. Physics of the Solid State, 64(2), 168.
Aleshkin V. Ya., Dubinov A. A.; Gavrilenko V. I., Pavlov S. G. & H.-W.Hübers H. -W.
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Температурная зависимость уровня Ферми в узкозонных объемных пленках HgCdTe при различной концентрации вакансий ртути. Физика и техника полупроводников, 56(5), 463.
Козлов, Д.В.; Жолудев, М.С.; Румянцев, В.В.; Иконников, А.В.; Pavlov, S.; Hubers, H.-W. & Морозов, С.В.
