Electrical and optical properties of strongly reduced epitaxial BaTiO3-x thin films

A series of BaTiO3-x (x=0, 0.07, 0.18, and 0.48) thin films with c-axis ori ented tetragonal perovskite structures were epitaxially grown on SrTiO3 (10 0) and MgO (100) substrates by laser molecular-beam epitaxy under various o xygen pressures. The electrical conductivity of the deposited thin films in creases with decreasing the oxygen pressure. A metallic conduction is obser ved in the oxygen most deficient BaTiO2.52 thin film whose oxygen content ( 2.52) and electrical resistivity (6.0x10(-5) Omega cm) are both the minimum values among literature. An optical absorption peak is observed in each ox ygen deficient BaTiO3-x thin film. The peak position shifts to lower energy , and the peak width becomes larger with decreasing the oxygen pressure. Th e influence of oxygen pressure on the electrical and optical properties in the reduced BaTiO3-x thin films is discussed. (C) 2000 American Institute o f Physics. [S0003- 6951(00)01352-8].