High-Tc superconducting Bi-Sr-Ca-Cu-O thin films have been successfully prepared by low-pressure organometallic chemical vapor deposition using metallic silver as a substrate. N2O is employed as an efficient reactant gas in combination with the volatile metal-organic complexes Cu(acetylacetonate)2, Sr(dipivaloymethanate)2, Ca(dipivaloymethanate)2, and triphenyl bismuth (Bi(C6H5)3) as sources. X-ray diffraction measurements reveal that the as-deposited films deposited at 625-650°C contain a mixture of the Bi2(Sr,Ca)2CuOx and Bi2(Sr,Ca)3Cu2Ox phases, and that the proportion of the high-Tc phase increases with increasing deposition temperature. The post-annealed films are composed predominantly of the Bi2(Sr,Ca)3Cu2Ox phase with high preferential orientation of the crystallite c axes perpendicular to the substrate surface. Deposition on polycrystalline Ag substrates significantly improves the texture and morphology of BSCCO films as compared with films deposited on MgO. Possible mechanisms for the improvement of BSCCO films when using Ag as a substrate are discussed.
ASJC Scopus subject areas
- Condensed Matter Physics