Preparation And Properties Of Photosensitive YBCO Thin Films

The high temperature superconducting YBCO thin films is one of the important materials for the application of superconducting.Fine-patterning is essential to the application of YBCO films. Among various fabrication techniques of thin film ,the sol-gel process has attracted much interest for the preparation of YBCO thin film due to the advantages of good homogeneity , easy control composition , easy formation of large area thin films.In this paper, YBCO thin films with excellent property were prepared by Sol-Gel process, using inorganic salt as precursor. And the fine patterning of the films was fabricated by chemical modified method. The UV-Vis and FT-IR spectrometer was used to analyze the photosensitive property of the gel films. X-Ray diffraction meter , XPS and SEM were applied to study the crystal phase , the compositions and structures of YBCO films respectively. The results were shown as follows:(1)UV photosensitive chelate complex sol with Cu ions is obtained, using methanol as solvent, Cu(AC)2 as precursor, benzalacetone (BzAcH) as chemical modification, from which the film to be patterned can be prepared. And the optimal molar ratio was Cu²⁺:BzAcH = 1:1.The fiim produced on Si substrate by dip -coating was patterned. After heat treatment , the CuO films with specific fine pattern can be obtained.(2) UV photosensitive chelate complex sol with Y ions is obtained, using methanol as solvent, Y(AC)3 as precursor, benzalacetone (BzAcH) as chemical modification, from which film to be patterned can be prepared. And the optimal molar ratio was Y³⁺:BzAcH = 1:1. The fiim produced on Si substrate by dip -coating was patterned. After heat treatment , the Y2O3 films with specific fine pattern can be obtained.(3)A photosensitive YBCO sol can be prepared using BzAcH as chelator via Ba-TFA method. And the optimal molar ratio was Y³⁺:Ba²⁺:Cu²⁺:BzAcH = 1:2:4:5. The fiim produced on Si or LAO substrate by dip-coating was patterned. A fine-patterning can be fibricated by such percursor with ethyl alcohol as solvent. After heat treatment , the YBCO films with specific fine pattern can be obtained.(4) YBCO precursor films were prepared by a hybrid of Ba-trifluoroacetate (Ba-TFA) with non-fluorine containing Cu and Y solution precursors. Then the precursor films were converted at 800℃in N₂/O₂ for 1 h. and followed by oxygen annealing at 450℃in O₂ for 2-3 h..High performance YBCO films have been obtained . YBCO films were fabricated on the LAO(001)substrate .Their samllest room temperature sheet resistance were about 6Ω/â–¡.Tc measurements indicate sharp transitions with zero resistance above 89 K.