Thermally stimulated diffusion of Mn through thin layers of GaAs was studied by X-ray photo-emission. (Ga, Mn)As samples with 5 at% Mn were capped with 4, 6 and 8 monolayer (ML) GaAs, and Mn diffusing through the GaAs was trapped on the surface by means of amorphous As. It was found that the out-diffusion was completely suppressed for an 8ML-thick GaAs film. The short diffusion length was attributed to an electrostatic barrier formed at the (Ga, Mn)As/GaAs interface.

Thermal Diffusion of Mn through GaAs Overlayers on (Ga,Mn)As. J.Adell, I.Ulfat, L.Ilver, J.Sadowski, K.Karlsson, J.Kanski: Journal of Physics - Condensed Matter, 2011, 23[8], 085003