We have investigated the substitution effect of pentavalent bismuth ions on the electronic structure and physicochemical properties of barium indium tantalate. X-ray diffraction, X-ray absorption spectroscopic, and energy dispersive spectroscopic microprobe analyses reveal that, under oxygen atmosphere of 1 atm, pentavalent Bi ions are successfully stabilized in the octahedral site of the perovskite tantalate lattice. According to diffuse reflectance UV-vis spectroscopic analysis, the Bi substitution gives rise to the significant narrowing of band gap of barium indium tantalate even at a low Bi content of ∼5%, underscoring a high efficiency of Bi substitution in the band gap engineering. Such an effective narrowing of the band gap upon the Bi substitution would be attributable to the lowering of conduction band position due to the high electronegativity of BiV substituent. As a result of band gap engineering, the Ba(In0.5Ta0.5-xBix)O3 compounds with x ≥ 0.03 can generate photocurrents under visible light irradiation (λ > 420 nm). Based on the present experimental findings, it becomes clear that the substitution of highly electronegative p-block element like BiV ion can provide a very powerful tool for tailoring the electronic structure and physicochemical properties of wide band gap semiconductors.
|Number of pages
|Materials Research Bulletin
|Published - 2007 Nov 6
Bibliographical noteFunding Information:
This work was supported by the financial support by Ministry of Environment (Grant No.: 022-061-023) and partly by the SRC/ERC program of the MOST/KOSEF (grant: R11-2005-008-03002-0). The experiments at Pohang Accelerator Laboratory (PAL) were supported in part by MOST and POSTECH.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering