XAFS Study of metal-doped In2O3

In2O3 has attracted interest recently because of its favorable properties for potential applications as diluted magnetic semiconductors. For these applications the material must be doped to produce the desired magnetic properties, and it is essential to determine the fate of the dopants in order to optimize the materials and understand the magnetic measurements. This paper summarizes some recent XAFS studies of a series of In2O3 films doped with V, Cr, Co, and Fe. XAFS is shown to be a powerful tool to characterize these materials, providing valence information, and detecting both substitutional doping as well as second phase formation. V and Cr are found to take up well ordered substitutional sites with no evidence for second phase formation. For Co the substitutional sites were much more disordered than for V or Cr. Fe doped samples also displayed a range of results with well-ordered substitutional sites in some samples, while others showed extensive second phase formation including magnetite and Fe metal.