Surface electronic structure of clean and hydrogen-chemisorbed SixGe1-x alloy surfaces

Ja Hum Ku, Robert Nemanich

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The surface electronic states of clean and hydrogen-terminated SixGe1-x surfaces were studied with angleresolved ultraviolet photoelectron spectroscopy (ARUPS). A series of strained and relaxed SixGe1-x alloys were grown on Si(100) wafers using electron-beam evaporation in an ultrahigh-vacuum molecular-beamepitaxy chamber. The growth was followed by in situ hydrogen-plasma exposure to obtain H-terminated surfaces. After alloy film growth, a double domain 2×1 reconstruction was observed for the series of clean SixGe1-x alloys. A diffuse double domain 2×1 reconstructed surface was obtained after the h-plasma exposure, which implies that the Si(Ge)-H monohydride domains are smaller than the surface terraces. The diffuse peaks were attributed to disorder and incoherence in the H termination rather than a change of the terrace structure. He I (21.21 eV) and Ne I (16.85 eV) resonance lines were employed to identify the surface states or resonances and bulk states of all samples described in this paper. ARUPS spectra of the series of clean and H-terminated SixG1-x alloys were obtained as a function of emission angle along the [010] direction. From measurements of the series of clean SixGe1-x alloy surfaces the surface states or resonances due to the dangling bond and the back bond were identified and found to disperse downward from Γto J′ab. A nondispersive hydrogen-induced surface state or resonance was observed from the series of H-terminated SixG1-x alloy surfaces. The electron affinities of the series of clean and H-terminated SixGe1-x alloy surfaces were also measured using ARUPS. The electron affinity of the Si(100) surface was found to be 3.83 eV and those of strained and relaxed SixGe1-x (100) surfaces ranged from 3.87 to 4.05 eV. The electron affinity of clean and H-terminated surfaces exhibited the same values.

Original languageEnglish (US)
Pages (from-to)14102-14110
Number of pages9
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume54
Issue number19
StatePublished - Nov 15 1996
Externally publishedYes

Fingerprint

Electronic structure
Hydrogen
electronic structure
hydrogen
Ultraviolet photoelectron spectroscopy
Electron affinity
Surface states
ultraviolet spectroscopy
electron affinity
photoelectron spectroscopy
Plasmas
Dangling bonds
Electronic states
Ultrahigh vacuum
Film growth
incoherence
Electron beams
hydrogen plasma
Evaporation
resonance lines

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Surface electronic structure of clean and hydrogen-chemisorbed SixGe1-x alloy surfaces. / Ku, Ja Hum; Nemanich, Robert.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 54, No. 19, 15.11.1996, p. 14102-14110.

Research output: Contribution to journalArticle

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