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Photon drag investigations of current relaxation processes in a two-dimensional electron gas

Untersuchung des Photonschleppeffektes auf Stromrelaxations-Prozesse in einem zweidimensionalen Elektronengas
: Graf, S.; Sigg, H.; Köhler, K.; Bächtold, W.


Physical Review. B 62 (2000), No.15, pp.10301-10309
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Journal Article
Fraunhofer IAF ()
III-V semiconductor; III-V Halbleiter; superlattice; Übergitter; optical measurement; optische Messung

We have investigated the photon drag current that is excited by an infrared laser beam in the plane of the two-dimensional electron gas of GaAs/Al(0.35)Ga(0.65)As multiple-quantum-well systems. An analysis of the spectral response, measured with the picosecond infrared pulses of the wavelength-tunable free electron laser source FELIX, is presented for different doping schemes and examined as a function of temperature and intensity. The influence of the subband-selective scattering by a delta doping is explored, which demonstrates that the photon drag spectral response allows the determination of the momentum relaxation time ratio, R = tau1/tau2, of the electrons in the ground and excited subbands. The relaxation time ratio is found to be surprisingly constant over a large temperature range. The variation of the ratio with intensity can be attributed to heating of the electron gas, whose temperature exceeds 1000 K at saturation intensity.