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G. Knebl

Publications and source records attributed to G. Knebl.

2 recordsLinked to original sources

Optical mapping of non-equilibrium charge carriers

We investigate the energy relaxation segmentation in a resonant tunneling heterostructures by assessing the optical and transport dynamics of non-equilibrium charge carriers. The electrical and optical properties are analyzed using electronic transport measurements combined with electro- and photoluminescence spectroscopies in continuous-wave mode. The radiative recombination is mainly governed by the creation of heavy holes \textit{via} impact ionization processes. Our results suggest hot electrons and holes populations form independent non-equilibrium systems that do not thermalize among them and with the lattice. Consequently, the carriers effective temperature changes independently at different regions of the heterostructure, with a population distribution for holes colder than for electrons.

cond-mat.mes-hall

Circular and Linear Photogalvanic Effects in Type-II GaSb/InAs Quantum Well Structures in the Inverted Regime

We report on the observation of photogalvanic effects induced by terahertz radiation in type-II GaSb/InAs quantum wells with inverted band order. Photocurrents are excited at oblique incidence of radiation and consists of several contributions varying differently with the change of the radiation polarization state; the one driven by the helicity and the other one driven by the linearly polarization of radiation are of comparable magnitudes. Experimental and theoretical analyses reveal that the photocurrent is dominated by the circular and linear photogalvanic effects in a system with a dominant structure inversion asymmetry. A microscopic theory developed in the framework of the Boltzmann equation of motion considers both photogalvanic effects and describes well all the experimental findings.

cond-mat.mes-hall