Composition Dependent Mobility And Bandgaps In (La0.05baxsr0.95-X)Sno3 Epitaxial Films

Perovskite stannates ASnO(3) (A=Ba, Sr) as transparent conducting oxides have recently attracted much attention due to their high electron mobility and high optical transparency. Here, we investigated experimentally and theoretically the composition-dependent structural, electrical, and optical properties of (La0.05BaxSr0.95-x)SnO3 (LBSSO, x=0-0.95) thin films. Detailed x-ray diffraction characterization studies show that the LBSSO films were epitaxially grown on the LaAlO3(001) substrates. The out-of-plane lattice constants of the LBSSO films increase from 4.045 to 4.122 angstrom with incorporation of the Ba content from 0 up to 0.95 in the films. The electron mobility values of the films increase gradually from 22.2 to 34.4cm(2)/Vs with the increasing Ba contents. The direct/indirect optical bandgaps decrease monotonously from 4.64/4.04 to 4.05/3.40eV upon changing the Ba content from 0 to 0.95. Density functional theory calculations indicated that the Ba substitution can reduce the electron effective mass and the bandgaps, leading to a higher carrier mobility.