Optical spectroscopy: An in situ diagnostic for pulsed laser deposition of high Tc superconducting thin films.

High oxygen partial pressure has been found to be an important parameter for the pulsed laser deposition of as-deposited superconducting thin films with high Tc and Jc. The optical emissions from both elemental and oxide species ejected from the target of YBa2Cu3O7-x during the pulsed laser deposition process increase with the oxygen pressure, with the oxide emission showing a stronger pressure dependence than the elemental emission. The dynamics of the interaction between the oxygen atoms and the species in the laser-produced plume were studied by a wavelength and time-resolved measurement. The results are qualitatively explained using a simple model based on optical emission arising from inelastic and recombination collision between the elemental species and electronically excited oxygen atoms. The formation of oxides in the plume is shown to be essential for the production of higher quality superconducting films, indicating the value of optical spectroscopy as a diagnostic tool. [ABSTRACT FROM AUTHOR]