Phase diagram and crystal growth of Mn-substituted CuInSe2 system and their defect properties

In order to obtain newer materials with better diluted magnetic semiconductor (DMS) performance, we have constructed the phase diagrams of Mn-substituted CuInSe2 systems, using differential thermal analysis and powder X-ray diffraction. Based on these phase diagrams, which show that the Mn-substituted CuInSe2 solid solutions are obtained, bulk crystals were grown by the horizontal gradient freezing method. The grown crystals substituted by Mn atom in Cu- and In-site have compositional homogeneity, and n- and p-type conductions, respectively, and seem to become a degenerated semiconductor for heavy Mn doping. The optical band gaps of the crystals substituted by Mn atom in Cu- and In-site were a little larger and narrower, respectively, than that of non-doped CuInSe2. The changes of electrical and optical properties indicated that Mn atoms were certainly substituted for two kinds of cations in CuInSe2.