Auger-photoelectron coincidence spectroscopy of SiO2

The O K-LL spectrum from a SiO2 surface was measured in coincidence with O 1s photoemission in SiO2. The coincidence lineshapes are compared to the simultaneously obtained conventional Auger lineshapes and to model lineshapes. The low-energy tail of the O K-LL lineshape from SiO2 is suppressed in the APECS spectrum due to discrimination against extrinsic loss and initial-state shake processes, but remaining intensity indicated significant contribution from final-state shake-up/off processes. The results also confirm that a low energy satellite to the O K-L2,3L2,3 Auger line that is eliminated in the coincidence spectrum, and a high-energy shoulder that is enhanced in the coincidence spectrum, arise from an initial-state shake process, and final-state correlation effects, respectively. The results demonstrate the viability of applying APECS to the study of other metal oxides via the anion.