Conductivity Testing and Electrical Properties Analysis of Rare-earth-based Single Crystal Substrates

This study aims to systematically investigate the electrical conductivity characteristics of various single-crystal oxide substrates for applications such as high-temperature fuel cells. Using the two-terminal conductivity testing method, the conductivities of nine single-crystal substrates (YSZ, YAO, LAO, NGO, LSAT, STO, LSGM, TSO, and GSO) were measured under varying oxygen partial pressure and temperature conditions. The changes in conductivity properties with environmental variations and their underlying mechanisms were analyzed. To achieve good electrical conductivity, metal Pt with a thickness of 100 nm was deposited on the substrate surface using magnetron sputtering technology. The results demonstrated that YSZ and LSGM exhibited excellent ionic conductivity under the test conditions, independent of oxygen partial pressure. STO showed significant electrical conductivity transitions, exhibiting n-type conductivity in reducing atmospheres and p-type conductivity in oxidizing atmospheres. Other substrates, such as NGO, GSO and LAO exhibited ionic conductivity under low oxygen partial pressure but transitioned to hole conductivity under high oxygen partial pressure. This study reveals the diversity of electrical conductivity characteristics of single-crystal substrates and their sensitivity to environmental conditions, providing key data support for the material design and optimization of high-temperature fuel cells and other electrochemical devices.