Effects of Mn substitution on the structure and properties ofchalcopyrite-type CuInSe2

摘要

Mn-doped CuInSe_2compounds (Culn_(1-x)Mn_xSe_2,x = 0.0125-0.20 and Cu_(1-y)in_(Mn_(2y)Se_2,2y = 0.0125-0.60) were synthesized by high-temperature solid-state reactions. Single phase materialswith chalcopyrite structure persist up to 0.10 and 0.20 doping for Culn_(1-x)Mn_xSe_2and Cu_(1-y)ln_(l-Mn_(2y)Se_2,respectively. The chalcopyrite and sphalerite phases co-exist in the Cu_(1-y)ln_(1-Mn_(2y)Se_2system for2y = 0.25-0.50. Attempts to introduce greater manganese content, x = 0.15-0.20 for Culn_(1-x)Mn_xSe_2and2y = 0.60 for Cu(1-y)ln_(l-Mn_(2y)Se_2, result in partial phase segregation. For the single-samples, thelattice parameters of both systems increase linearly with manganese concentration and thus followVegard's law. The temperature of the chalcopyrite-sphalerite phase transition is decreased by manganesesubstitution for all single-phase samples. The bandgap of the materials remains around 0.9 eV. Additionally,the Mn-doped CuInSe_2compounds display paramagnetic behavior, whereas pure CuInSe_2is diamagnetic at5-300 K. All the Culn_(1-x)Mn_xSe_2and Cu_(y)ln_(Mn_(2y)Se_2compounds withchalcopyritestructure showantiferromagnetic coupling and measured effective magnetic moments up to 5.8μ_B/Mn.