Quantitative measurement of manganese incorporation into (In,Mn)As islands by resonant x-ray scattering

In this paper we present a method to determine the occupation of Mn ions in epitaxial (In,Mn)As nanostructures by resonant x-ray diffraction near the Mn $K$-absorption edge, exploiting the dependency of the intensity of both (200) superstructure and the (400) fundamental reflections. The concentrations of Mn atoms on substitutional In sites, as well as on In- and As-interstitial sites, were unambiguously determined. A threshold concentration for the interstitial sites, which are occupied first for low nominal Mn deposition content, was found. Calculations using density-functional theory indicate that a higher occupancy of such sites can be favorable with respect to the occupation of substitutional sites, depending on surface potentials and growth kinetic effects.