  We present the manipulation of magnetic and electrical properties of
(Ga,Mn)As by the adsorption of dye-molecules as a first step towards 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
GaMnAs/fluorescein system with respect to (Ga,Mn)As. Upon exposure to visible
light a shift in Curie temperature towards higher values and a reduction of the
coercive field can be achieved in photo-sensitized (Ga,Mn)As. A mayor change in
the XPS spectrum of (Ga,Mn)As indicates the appearance of occupied levels in
the energy range corresponding to the (Ga,Mn)As valence band states upon
adsorption of fluorescein. This points towards a hole quenching effect at the
molecule-(Ga,Mn)As interface which is susceptible to light exposure.

Materials Science;Other Condensed Matter