Polarization resolved luminescence in asymmetric n-type GaAs/AlGaAs resonant tunneling diodes

We have investigated the polarized emission from a n-type GaAs/AlGaAs resonant tunneling diode under magnetic field. the GaAs contact layer emission shows a large constant negative circular polarization. A similar result is observed for the quantum well, but only when electrons are injected from the substrate, while for inverted biases, the polarization tends to become positive for small voltages and large laser excitation intensities. We believe that the quantum well polarization may be associated to the partial thermalization of minority carriers on the well subbands and is thus critically dependent on the bias-controlled density of carriers accumulated in the well.Universidade Federal de São Paulo, Dept Fis, BR-13565905 São Paulo, BrazilUniv Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, BrazilUniv Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, EnglandUniv Sheffield, Dept Elect & Elect Engn, Sheffield S1 3JD, S Yorkshire, EnglandUniversidade Federal de São Paulo, Dept Fis, BR-13565905 São Paulo, BrazilWeb of Scienc