Substrate-film lattice engineering for the growth by spin coating Of c –Axis and Non- C -Axis BSCCO HTS epitaxial thin films

Abstract

For the fabrication of new devices taking advantage of interface phenomena, growth of thin films with different orientations is necessary. Epitaxial thin films of c -axis type (001) Bi-2201, (001) Bi-2212, and (001) Bi-2223 and of non- c -axis type (115) Bi-2201, (117) Bi-2212, and (119) Bi-2223 were grown by spin coating and subsequent annealing on single-crystal substrates of SrTiO 3, MgO, or LaAlO 3 with (001) and (110) orientations, respectively. We show that lattice matching relationship between the substrate and the film is the key condition for the orientation control in Bi–Sr–Ca–Cu–O thin films obtained by this route. This is similar to Bi–Sr–Ca–Cu–O films grown by vapor deposition methods. Therefore, it is concluded that the growth method is not essential for the orientation control of the film. However, for the epitaxial growth it is necessary to ensure a high mobility of the atomic species at the substrate-film interface and for the spin-coated films this criterion suggests the presence of a liquid at the interface during annealing. Our films have shown specific structural features and occurrence of impurity phases or orientations. Further research is required. Our work suggests that the growth by spin coating or by related chemical methods of high-quality epitaxial oxide thin films is a promising research direction.