Spin polarization of carriers in resonant tunneling devices containing InAs self-assembled quantum dots

In this work, we have investigated transport and optical properties of n-i-n resonant tunneling diodes (RTDs) containing a layer of InAs self-assembled quantum dots (QDs) grown on a (311)B oriented GaAs substrate. Polarization-resolved photoluminescence (PL) and magneto-transport measurements were performed under applied voltage and magnetic fields up to 15 T at 2 K under linearly polarized laser excitation. It was observed that the QD circular polarization degree depends strongly on the applied voltage. Its voltage dependence is explained by the formation of excitonic complexes such as positively (X+) and negatively (X−) charged excitons in the QDs. Our results demonstrate an effective electrical control of an ensemble of InAs QD properties by tuning the applied voltage across a RTD device into the resonant tunneling condition.