ELECTRICAL INJECTION AND OPTICAL READOUT OF SPIN STATES IN A SINGLE QUANTUM DOT

We demonstrate electrically driven spin injection into a single semiconductor quantum dot. Spin polarized electrons are transferred from a diluted magnetic semiconductor ( ZnMnSe ) into InAs quantum dots embedded into GaAs barriers. The spin information can be extracted directly from the polarization degree of the electroluminescence signal stemming from an individual quantum dot. By slightly modifying the device design, we demonstrate a concept to electrically charge the quantum dot by a spin polarized electron and present a simple way to probe this spin state optically.