Evidence of suppressed hot carrier relaxation in type-II InAs/AlAs 1-x Sb x quantum wells

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Role of Exciton Binding Energy on LO Phonon Broadening and Polaron Formation in (BA) 2 PbI 4 Ruddlesden–Popper Films

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Control of hot carrier thermalization in type-II quantum wells: a route to practical hot carrier solar cells

International audienceHot carrier distributions generated by the absorption of high-energy photons typically etherealize rapidly via various phonon-mediated relaxation processes. In this paper, it is shown that type-II quantum wells (QWs) exhibit stable non-equilibrium carrier distributions, which can be manipulated and stabilized independent of the photonic dispersion of the constituent materials. Moreover, it will be shown that the reduced overlap between electron and hole wave functions in type-II QWs, which inhibit radioactive recombination, play a critical role in hot carrier thermalization in these systems. Current-voltage characteristics from analogous MQW p-i-n structures show enhanced hot carrier photocurrent extraction with increasing optical excitation power. Specifically, upon increased photo-excitation the elevated thermal energy in the carrier distribution results in the tunneling of hot electrons from the QW and increased photo carrier collection

Valence band states in an InAs/AlAsSb multi-quantum well hot carrier absorber

In this study, detailed temperature dependent simulations for absorption and photogenerated recombination of hot electrons are compared with experimental data for an InAs/AlAsSb multi-quantum well. The simulations describe the actual photoluminescence (PL) observations accurately; in particular, the room temperature e1-hh1 simulated transition energy of 805 meV closely matches the 798 meV transition energy of the experimental PL spectra, a difference of only 7 meV. Likewise, the expected energy separations between local maxima (p1-p2) in the simulated/experimental spectra have a difference of just 2 meV: a simulated energy separation of 31 meV compared to the experimental value of 33 meV. Utilizing a non equilibrium generalized Planck relation, a full spectrum fit enables individual carrier temperatures for both holes and electrons. This results in two very different carrier temperatures for holes and electrons: where the hole temperature, T-h, is nearly equal to the lattice temperature, T-L; while, the electron temperature, T-e, is 'hot' (i.e., T-e > T-L). Also, by fitting the experimental spectra via three different methods a 'hot' carrier temperature is associated with electrons only; all three methods yield similar 'hot' carrier temperatures