Shi et al. Nanoscale Res Lett 2011, 6:50 http://www.nanoscalereslett.com/content/6/1/50 Page 3 of 5 Figure 1 In 3d5/2 Core level XPS spectra for a InN and e InN/diamond samples, and C1s XPS spectra for c diamond and f InN/diamond samples. b InN and d diamond are the valence band spectra. All peaks have been fitted using a Shirley background and Voigt (mixed Lorentzian-Gaussian) line shapes, as summarized in Table 1. Based on all the arguments made above, we attribute the lower-binding energy component (443.42 eV) in Figure 1a to the “screened” final-state peak in In3d5/2 photoemission, the higher-binding energy component (445.27 eV) to the “unscreened” final-state peak, and the mid-binding energy component (444.21) to the In–O bonding. In Figure 1c, the lower-binding energy compo- nent (284.9 eV) and the higher-binding energy compo- nent (286.00 eV) are considered to be C–C bonding and C–O bonding respectively [28,29]. In order to avoid the surface oxidation and reduce the contamination effect, the InN/diamond sample was