Determining the Interface Conductivity of Nb-SrTiO₃ (Nb-STO) with Various Electrodes

Solid oxide fuel cells have the potential to function within efficient systems of energy infrastructure. Nb-doped SrTiO₃ (Nb-STO) (001) is an n-type semiconductor which has the potential to provide electrical contact for application in solid oxide fuel cells. We study the interface conductivity of Nb-STO with various metal and oxide contacts as a function of temperature (200°C-550°C) and oxygen partial pressure (10^-5 - 0.2 atm). We consider the interface of Nb-STO with metal contacts of Cr and oxide contacts of vertically aligned STO (100) and Sm-doped ceria (SDC) (100) through the fabrication of symmetric electrode devices. This presentation examines the interface electrical characteristics of Nb-STO with the two electrode materials studied. Overall, we demonstrate that Cr metal can provide contact to Nb-STO without resulting in a Schottky barrier, while vertically aligned STO (100) and Sm-doped ceria (100) nanocolumns cannot provide contact at elevated temperatures. The results of this study have implications on the use of single crystal Nb-STO as a conductive substrate for electrolyte materials in solid oxide fuel cells.