Solid solubility of rare earth elements (Nd, Eu, Tb) in In2−xSnxO3 – effect on electrical conductivity and optical properties

摘要

Wide band-gap semiconductors doped with luminescent rare earth elements (REEs) haveudattracted recent interest due to their unique optical properties. Here we report on theudsynthesis of the transparent conducting oxides (TCOs) indium oxide and indium tin oxideud(ITO) doped with neodymium, europium and terbium. The solid solubility in the systemsudwas investigated and isothermal phase diagrams at 1400 °C were proposed. The solubility ofudthe REEs in In2O3 is mainly determined by the size of the rare earth dopant, while in ITO theudsolid solubility was reduced due to a strong tendency of the tin and REE co-dopants to formuda pyrochlore phase. The effect of the REE-doping on the conductivity of the host wasuddetermined and optical activity of the REE dopants were investigated in selected hostudmaterials. The conductivity of sintered materials of REE-doped In2O3 was significantlyudreduced, even at small doping concentrations, due to a decrease in carrier mobility. Theudsame decrease in mobility was not observed in thin films of the material processed at lowerudtemperatures. Strong emissions at around 611 nm were observed for Eu-doped In2O3,uddemonstrating the possibility of obtaining photoluminescence in a TCO host, while noudemissions was observed for Nd- and Tb-doping.