A study of oxygen diffusion in and out of YBa2Cu3O7-delta thin films

An in situ investigation of oxygen diffusion in and out of YBa2Cu3O7-delta thin films was conducted using real time ellipsometry. The ellipsometric spectra were obtained for photon energy range from 1.4 to 4.5 eV for varying film thickness. Oxygen out-diffusion was found to be a function of film thickness, while the effect on in-diffusion was negligible. The out-diffusion was also greatly affected by the exposure to H20. The results provided strong evidence that the mechanisms for the two processes were different.