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Abstract: The morphological characteristics and electronic structure of the BaTiO3 films grown by pulsed-laser deposition technique have been investigated. AFM and FE-SEM images reveal columnar growth characteristic of these films. Utilizing spectrophotometer, optical band gap of the films were reckoned to be about 3.76eV. Both dα/dE and PL vs. E plots reveal numerous luminance states in the gap. Despite the presence of many luminance faults in the gap, cations manage to preserve their electronic states. [Copyright &y& Elsevier]

Abstract: The electronic conductor-insulator transition in Ca-doped BiFeO3 films grown by pulsed-laser deposition technique has been investigated. Nature of the transition is resolved to be Mott type through the control of band-filling. Calcium resolved to have colossal effect on enhancing the electrical conductivity of BiFeO3, but it did not affect band gap of the mother phase perceptibly. UV-visible study yielded band gap of 2.72-2.81eV (at 300K) for different concentrations of calcium. Both UV-visible and photoluminescence spectra revealed sub-band gap transitions at 2.17 and 2.38eV, of which the latter might be ascribed to the oxygen vacancies. [Copyright &y& Elsevier]