Some Practical Applications Of Elastic Peak Electron-Spectroscopy

Practical applications of elastic peak electron spectroscopy (EPES) are presented to demonstrate the advantages of this technique in the study of materials subjected to electron beam degradation and surfaces involving hydrogen species. Beam damage on phthalocyanine layers is detected at low beam power (E(p) = 500 eV, J(p) = 10(-3) A cm-2, grazing incidence angle 20-degrees) with a cross-section of about 8 x 10(-18) cm2, as deduced from EPES experiments. The change in the emission yield of elastically reflected electrons during electron irradiation of this 'fragile' molecular material is related to an increase in the mean atomic number due to breaking of C-H bonds and to desorption of hydrogen. Using very low current density to prevent primary beam effects, the distinction between different metal phthalocyanine layers (PcZn and Pc2Lu) and the study of diffusion induced by heat treatments are possible by EPES, in contrast to AES and EEIS (electron energy loss spectroscopy) techniques. Application of EPES to the analysis of titanium alloy TA6V submitted to a hydrolysis treatment in hot water is also reported. The enhancement in elastic scattering with decreasing primary energy suggests that hydrogen is present at the surface of the hydrolysed sample.