  Mn-doped GaAs thin films were grown at a high substrate temperature of 580 C.
During the growth process, the Mn cell temperature was ramped at different
rates, resulting in a variety of different Mn concentration depth profile
slopes, as measured using dynamic secondary ion mass spectrometry (SIMS).
Results show that controlling the Mn deposition rate via temperature during
molecular beam epitaxy (MBE) growth can mitigate the effect of Mn atoms
diffusing toward the surface. Most importantly, the slope of the Mn
concentration as a function of depth inside the sample can be tuned from
negative to positive.
