Magnetism and carrier modulation in (Ga,Mn)As/organic-dye hybrid devices

We present the manipulation of magnetic and electrical properties of Ga,Mn As via the adsorption of dye-molecules as a step toward the realization of light-controlled magnetic-semiconductor/dye hybrid devices. A significant lowering of the Curie temperature with a corresponding increase in electrical resistance and a higher coercive field is found for the Ga,Mn As/fluorescein system with respect to Ga,Mn As. Upon exposure to visible light a shift in Curie temperature toward higher values as well as a reduction of the electrical resistance and the coercive field can be achieved. This points toward a hole quenching effect at the molecule- Ga,Mn As interface which is susceptible to light exposure.