Ti 2p (a,c,e,g) and C 1s (b,d,f,h) photoemission spectra for clean (a,b) and oxidized (c-h) TiC (755) single crystal before (gray) and after (black) Li2O2 deposition measured at ultimate surface sensitivity provided by electron kinetic energy of 50 eV. A clean vicinal (755) TiC surface was obtained by annealing the single crystal in oxygen (10-7 mbar) at 1150 °C for 20 min and further "flashing" up to 1300 °C for several times. Such a procedure allowed one to eliminate oxygen from the surface; residual oxygen intensity never exceeded 5 at. % for the layer probed with a photoelectron kinetic energy of 200 eV. Fresh Li2O2 was deposited by evaporation of metallic Li under oxygen pressure of ~10-7 mbar in the preparation chamber of the spectrometer. Dots show experimental data, while solid lines represent fitted curves. Components are shown for spectra recorded after Li2O2 deposition. Insets demonstrate component fractions in spectra before (left bars) and after (right bars) Li2O2 deposition.
Close