Abstract

Abstract The carrier dynamics in a 5nm Al 0.4 Ga 0.6 As/GaAs single quantum well which is exposed to an electric field perpendicular to the quantum well plane have been studied at low temperature by means of picosecond luminescence, photoluminescence excitation as well as photocurrent excitation spectroscopy. Three different relaxation channels of the photoexcited carriers in different regimes of the electric field strength are observed. Excitons are formed at low electric fields. A strong quenching of the exciton luminescence and an increase of the impurity or defect related luminescence is observed for fields up to 10 4 V/cm. The application of higher electric fields of ∼5×10 4 V/cm leads to an efficient extraction of free carriers out of the quantum well as demonstrated by the increase of the photo-current. The carrier escape explains the accompanying quenching of the extrinsic luminescence at any excitation energy between 1.63eV and 1.77eV. Time-resolved measurements show that the extrinsic and intrinsic luminescence decay times are not significantly changed with increasing electric field. The quenching of the intrinsic and extrinsic luminescence is thus explained by the decrease of the density of carriers which can recombine via exciton and impurity or defect related luminescence.

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