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