In (a) the measured and fitted O , P , and Li core-level emission lines obtained from the measurement of a thick layer of lithium phosphate on ITO are depicted. The scaled up error curve in the lower part of each graph illustrates the accuracy of the fit. With these data the composition of the layer is determined and yields and . In (b) the associated UP-spectrum illustrating the valence band region is shown. The valence band cut-off has been marked with dotted lines. Near this region gap states can be observed extending deeply into the gap.
(a) Evolution of the C , N , and Al core-level lines for with deposited stepwise on top. The bottom spectrum belongs to the pristine substrate prepared on ITO. In (b) the intensity and position normalized C and N spectra are shown.
Development of the UP-spectra in the valence band region for with deposited stepwise on top. In the pristine spectrum and the spectrum with lowest coverage (0.45 Å), the HOMO cut-offs are marked. Between these values a pronounced shift of 660 meV is found.
(a) Evolution of the Al core-level spectra for an Al substrate with deposited stepwise on top. (b) Detail of the survey spectra in order to illustrate the Al line and its plasmon lines, which are marked by arrows. Energy losses to conduction electrons occur in well-defined quanta characteristic of each metal (for Al about 16 eV). It can be observed that the first bulk plasmon line marked by a dotted line superimposes the P lines, yet according to the inset for the thickest deposited layer, the twofold structure of the P line originating from and can be clearly resolved. (c) Change in the work function of an Al layer with the layer thickness deposited on it. The data points were obtained by the analysis of the according UP-spectra and by KP measurements as already reported in our previous article (Ref. 1).
Fitted emission line position of the O , P , and Li components and the accordant calculated P:O and Li:P atomic ratios. In the last column the corresponding stoichiometry is given.
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