Figure 3
From: Graphite to diamond transition induced by photoelectric absorption of ultraviolet photons
Electron energy loss spectra (EELS) of the UV processed HOPG: (a) Location of the slit on the material, (b) long-slit spectra, (c) averaged spectra in the HOPG substrate and in the bump. In (c) the location of the spectral signature of graphite’s Π* bond is marked. Note that the Π* bond signature is weaker in the bump but still present, meaning that the bump is not pure diamond. The ratio of the signal in the Π* and σ* spectral bands (c) is used to define the sp2/sp3 index that it is displayed in (d). The signal in the Π* spectral band is minimal on the surface and increases inwards.
