ELECTRON-STIMULATED DESORPTION OF POSITIVE AND NEGATIVE OXYGEN IONS FROM YBA2CU3O7 SURFACES

Electron-stimulated desorption of positive and negative oxygen ions fr om YBa2Cu3O7 surfaces has been studied as a function of electron kinet ic energy in the 70-600 eV range. It has been found that the threshold electron kinetic energy needed to induce positive oxygen ion desorpti on occurs at 260+/-5 eV, whereas that associated with negative oxygen ion desorption was found to be 100+/-5 eV. These electron kinetic ener gies correspond to Cu, Y, and Ba core-level binding energies. These re sults suggest that negative and positive oxygen ion desorption may be initiated via a primary core level ionization. (C) 1995 American Insti tute of Physics.