Surface electronic states of low-temperature H-plasma-exposed Ge(100)

Jaewon Cho, R. J. Nemanich

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Abstract

The surface of low-temperature H-plasma-cleaned Ge(100) was studied by angle-resolved UV-photoemission spectroscopy and low-energy electron diffraction (LEED). The surface was prepared by an ex situ preclean followed by an in situ H-plasma exposure at a substrate temperature of 150-300°C. Auger-electron spectroscopy indicated that the in situ H-plasma clean removed the surface contaminants (carbon and oxygen) from the Ge(100) surface. The LEED pattern varied from a 1×1 to a sharp 2×1, as the substrate temperature was increased. The H-induced surface state was identified at ∼5.6 eV below EF, which was believed to be mainly due to the ordered or disordered monohydride phases. The annealing dependence of the spectra showed that the hydride started to dissociate at a temperature of 190°C, and the dangling-bond surface state was identified. A spectral shift upon annealing indicated that the H-terminated surfaces were unpinned. After the H-plasma clean at 300 °C the dangling-bond surface state was also observed directly with no evidence of H-induced states.

Original languageEnglish (US)
Pages (from-to)12421-12426
Number of pages6
JournalPhysical Review B
Volume46
Issue number19
DOIs
StatePublished - Jan 1 1992
Externally publishedYes

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ASJC Scopus subject areas

  • Condensed Matter Physics

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