High resolution electron energy loss spectroscopy study of clean, air-exposed and methanol-dosed Ge(1 0 0) surface

Using high resolution electron energy loss spectroscopy (HREELS), we have characterized the fingerprint spectra of clean, hydrogenated, methanol-dosed and air-exposed n-doped Ge(1 0 0). On clean Ge(1 0 0) 2 × 1, we report the observation of a surface phonon peak between ∼28–35 meV. The position and shape of this peak is sensitive to the presence of low surface coverage of hydrogen and oxygen. By adsorbing molecular hydrogen on the n-doped Ge, this peak shifts towards the elastic peak, and becomes attenuated. The HREELS fingerprint spectrum of air-exposed Ge is similar to that created by dosing Ge with methanol. Methanol undergoes dissociation into methyl radicals and hydroxyl species on Ge surfaces at room temperature and oxidizes the Ge surface readily.