Structural, electrical and optical properties of lanthanum-doped barium stannate

Ba1−xLaxSnO3 compounds were prepared by a conventional solid-state reaction method and their structural, electrical and optical properties were analyzed in this work. X-ray diffraction investigations revealed that La substitution in BaSnO3 led to the increase of cubic lattice parameters, whereas secondary phase appeared at x=0.1 or above. Evidences of the Sn4+ state and oxygen vacancies were clearly observed in X-ray photoelectron spectroscopy. The semiconductor behavior in temperature-dependent resistivity was found to obey the variable-range hopping conduction mechanism. With the help of absorption spectra, smaller band-gap energy and larger Urbach tail energy were observed in Ba0.93La0.07SnO3, as compared with Ba0.97La0.03SnO3, which was discussed in the frame of the role of structural disorder.