Determination of the effective mass and nanoscale electrical transport in La-doped BaSnO3 thin films

Epitaxial La-doped BaSnO3 thin films were grown by radio-frequency (RF) magnetron sputtering technique on (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (001) substrates. The n-type degenerate semiconductor was demonstrated in the La-doped BaSnO3 thin film from Hall-effect measurement, and its electron effective mass ∼0.396m0 (m0, the free electron mass) was determined from combined Seebeck coefficient and carrier density. Additionally, the local current-voltage curve measured using conductive atomic force microscopy exhibits non-linear characteristic and the transport mechanism at high bias is found to be the Fowler-Nordheim tunneling.