  We report a clear correspondence between changes in the Curie temperature and
carrier density upon annealing in epitaxially grown (Ga,Mn)As layers with
thicknesses in the range between 5 nm and 20 nm. The changes are dependent on
the layer thickness, indicating that the (Ga,Mn)As - GaAs interface has
importance for the physical properties of the (Ga,Mn)As layer. The
magnetoresistance shows additional features when compared to thick (Ga,Mn)As
layers, that are at present of unknown origin.
