EXPONENTIAL DECREASE OF THE XPS SIGNAL OF SUBSTRATE WITH THE INITIAL GROWTH OF Y1BA2CU3O7-DELTA OVERLAYER

Abstract

The initial growth of Y1Ba2Cu3O7-delta, (YBCO) thin film with 0 angstrom to 100 angstrom thickness on the SrTiO3 substrate was investigated by the in-situ measurement of X-ray photoemission. The exponential decrease of the XPS signal of substrate elements as a function of the thickness of YBCO overlayer, implies no island formation in the initial growth of thin film. This result is in contrast to the STM observations, which reveal the spiral expanding step edged island structure in the thicker film.