Investigation of lithium adsorption on the surface of TiO2 by electron-stimulated desorption

The electron-stimulated desorption (ESD) of lithium and oxygen ions has been measured from lithium layers adsorbed at temperatures 300-900 K on TiO2 thin polycrystalline films preliminary heated in the temperature range 300 < T < 1900 K. The layers of TiO2 are prepared by oxidation of titanium films previously deposited on the tungsten surface at T = 1000 K. The ESD of lithium and oxygen ions is initiated by ionization of the oxygen 2s level. In the temperature range 1200 < T < 1700 K substantial changes in Li+ and O+ ions yields are observed, and are associated with surface reconstruction in freshly formed TiO2 layers. In the temperature range from 300 to 900 K the ESD yield for Li+ changes reversibly with temperature For dose of deposited lithium n(Li) < 10(15) at/cm(2). (C) 2001 Elsevier Science B.V. All rights reserved.