Investigation of local structures around Mn atoms in In_1-xMn_xAs diluted magnetic semiconductors using EXAFS

Extended x-ray absorption fine structure (EXAFS) techniques have been used to investigate the local structures in In_1-XMn_XAs films grown by molecular beam epitaxy (MBE) under different processing conditions. For samples grown at low substrate temperatures (near 200°C) or with a low Mn concentration (about 1 atomic %), the Mn atoms can substitute for In in the InAs host, thus indicating that III-V diluted magnetic semiconductors (DMS) can indeed be prepared by substitutional doping of magnetic impurities. On the other hand, substitution dose not take place in high Mn concentration (above 10%) samples grown at high substrate temperatures (around 300°C); these samples contain a large amount of MnAs clusters and become ferromagnetic.