Optical Control of Electron Spins in Hybrid Quantum Structures of Diluted Magnetic Semiconductors

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The objective of the research program is following:1.Designing and fabrication of new hybrid nanostructures composed of II-VI compound diluted magnetic semiconductors and magnetic metals.2.Study of optical spin injection and spin relaxation in the hybrid nanostructures of quantum dots and quantum wells for the application on spin electronic devices.We have fabricated, for the above objectives, the quantum structures and hybrid nanostructures with CdTe,CdSe,ZnTe,ZnSe and magnetic materials of Mn and Co by using molecular expitaxy and electron beam lithography. Fabricated quantum nanostructures are studied by femtosecond laser spectroscopy by applying high magnetic fields. Spin injection processes of electrons, holes and excitons are investigated in the quantum wells and quantum dots of ZnMnSe-ZnSe,CdMnSe-CdSe and CdMnTe-CdTe systems. Transient photoluminescence of excitons shows fast spin injection and spin relaxation processes in the quantum structures induced by the magnetic field. Ultrafast spin dynamics of carriers is investigated in the diluted magnetic double quantum wells by transient pump-probe spectroscopy. The spin injection dynamics of electrons and holes are clarified in femtosecond time domain. Hybrid nanostructures with the diluted magnetic semiconductors and the magnetic metals were fabricated by electron beam lithography technique. The diluted magnetic quantum disks in the hybrid structures show the Zeeman splitting without applying external magnetic field, which verifies the affection the ferromagnetic nano-scale magnets neighboring to the quantum disks. The obtained results in the present research have high possibilities for spin electronic applications.