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

Ba 1− x La x SnO 3 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 BaSnO 3 led to the increase of cubic lattice parameters, whereas secondary phase appeared at x =0.1 or above. Evidences of the Sn 4+ 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 Ba 0.93 La 0.07 SnO 3 , as compared with Ba 0.97 La 0.03 SnO 3 , which was discussed in the frame of the role of structural disorder. [ABSTRACT FROM AUTHOR]