Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 28 WEDNESDAY AFTERNOON
RIVA-SS-WeA-P.3 ELECTRON STIMULATED DESORPTION STUDY OF DEFCT
SITES ON THE MgO(100) SURFACE USING QUADRUPOLE MASS SPECTROMETRY
AND TIME OF FLIGHT. I. Colera * , J. L. de Segovia ** , D. Cáceres * , E. Román ** and R. González
* . * Departamento de Física. Universidad Carlos III de Madrid. Leganés. 28911 Madrid. Spain. **
Laboratorio de Física e Ingeniería de Superficies. Instituto de Ciencia de Materiales.
CSIC.Cantoblanco. 28049 Madrid. Spain
While the quadrupole mass spectrometer (QMS) is an excellent tool to identify desorbed ions and
energy thresholds in electron stimulated desorption (ESD) experiments, its analysis of the ion kinetic
energy distribution is questionable. However, time of flight (TOF) is an excellent technique to
analyse the ion energies by using the QMS as the driving tube for the time of flight. The simultaneous
use of the ESDQMS and ESDTOF techniques yields excellent results in the determination of the
ion nature, ion threshold, and ion energy distribution in the study of site defects of on the MgO(100)
surface. Defect sites are identified by exposing the MgO(100) surface to D 2 O and H 2 18 O. Thus, the
D and 18 O can be differentiated from the 16 O and H surface atoms. The energy of the exploring electrons
varied from 200 to 600 eV, and an intensity of 100 nA was used to avoid surface damage. The
sample charge was also studied as a function of the incident electron en energy.
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