FRENKEL-WANNIER-MOTT EXCITON-STATES IN ORGANIC-INORGANIC SEMICONDUCTOR QUANTUM-WELLS SUBJECTED TO A MAGNETIC-FIELD

The optical properties of nanostructures using composite organic-inorg anic semiconductors, are dominated by a new type of excitonic states. These new hybrid excitations can be described as Frenkel-Wannier-Mott excitons. Frenkel excitons have very strong oscillator strength while Wannier-Mott excitons are very sensitive to external perturbations: st atic electric and magnetic fields. Our interest is centred on mixed ex citon formation under magnetic field effects; calculations were perfor med for a system composed of a monolayer of organic semiconductor (ant hracene) weakly adsorbed at a single parabolic quantum well of inorgan ic semiconductor (ZnSe/ZnCdSe). The application of a magnetic field le ads to an additional confinement. With the transverse magnetic field, a changeover of the characteristic length resulting from inorganic wel l width and the cyclotron length is obtained from the application of t he magnetic Field. The lower states of the dispersion law for hybrid F renkel-Wannier exciton possess a minimum near the center of the Brillo uin zone. It is deepest with increase in the applied magnetic field.