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SnO2 and Cu-SnO2 thin films were fabricated by the sol-gel method. The influence of annealing temperature and copper addition on the morphology and microstructure of the films was studied using X-ray diffraction (XRD) and UV-Visible, respectively. The results show that the tetragonal rutile phase is evidenced by XRD with no other phases observed. The crystallinity of SnO2 and Cu-SnO2 thin films had been improved with the increasing annealing temperature. The grain size decreased after Cu doping. On theoretical, Pure and Cu-SnO2 were calculated by first-principles full potential linearized augmented plane wave ultra-soft pseudo-potential method to investigate band structure.

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The zero bias anomaly dependent on the preferred surface grain orientation of YBa2Cu3O7-δ ceramics has been investigated in the conductance curve of the tunneling characteristics. A tunnel junction was fabricated by evaporating Al metal onto the ceramics sample and then annealed to remove the oxygen-deficient layer. The preferred orientation and the oxygen deficiency on the surface were examined based on X-ray diffraction patterns and X-ray photoelectron spectra. There exist oriented grains with their c-plane parallel to the ceramics sample surface. These surface layers are oxygen-deficient. Using the junction fabricated on the oxygen-deficient grains, the zero bias anomaly appears on the dynamic conductance curve of the tunneling characteristics. This anomaly disappears when the junction is fabricated after mechanical polishing of the surface and annealed. One of the sources of zero bias anomaly is the existence of oxygen-deficient grains on the YBa2Cu3O7-δ surface.