Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Directing Arsenic Dimers on Ge(100)
Year:2012
Research Areas
  • Physics chemical and mathematical
Information
Abstract
Vicinal Ge(100) is the common substrate for state of the art multijunction solar cells grown by metalorganic vapor phase epitaxy (MOVPE). One crucial step regarding high performance devices is the surface preparation of the substrate prior to III-V heteroepitaxy. Single domain surfaces with double layer steps are desired to avoid anti-phase disorder, but there is a lack in understanding the surface preparation of vicinal Ge(100) in VPE ambient. Predominantly DB stepped Ge(100) surfaces terminated by monohydrides have been prepared under clean MOVPE reactor conditions [1]. Exposure to arsenic either from the precursor (TBAs) or from reactor residuals modifies the surface reconstruction differently regarding dimer configuration, step and domain structure [2]. A contaminationfree MOVPE to UHV transfer system enabled us to correlate in situ reflection anisotropy spectroscopy (RAS) with surface science tools. We observed characteristic features in the RA spectra of arsenic terminated vicinal Ge(100) surfaces prepared under TBAs and background arsenic, respectively. The associated LEED patterns showed almost single domain (2x1) and (1x2) reconstructions, respectively. The dominant orientation of the As dimers corresponds to the sign of the most prominent RAS peak. Accordingly, we observed transitions between preferential (1x2) and (2x1) surface reconstructions depending on temperature, supply and source of arsenic in situ with RAS. X-ray photoelectron spectra indicate slight differences in the arsenic coverage and STM images show differences in the step structure, possibly being reflected in the RA spectra at higher photon energies.
International
Si
Congress
24th General Conference of the Condensed Matter Division of the European Physical Society, 29th European Conference on Surface Science, Condensed Matter and Materials Physics Conference, 11th European Conference on Surface Crystallography
960
Place
Edinburgh (UK)
Reviewers
Si
ISBN/ISSN
0-000000-00-0
Start Date
03/09/2012
End Date
07/09/2012
From page
1
To page
1
Proc. CMC-24, ECOSS-29, CMMP-12, ECSCD-11
Participants
  • Autor: O. Supplie
  • Autor: S. Brückner
  • Autor: Enrique Barrigon Montañes (UPM)
  • Autor: J. Luczak
  • Autor: P. Kleinschmidt
  • Autor: Ignacio Rey-Stolle Prado (UPM)
  • Autor: H. Doescher
  • Autor: T. Hannappel
Research Group, Departaments and Institutes related
  • Creador: Centro o Instituto I+D+i: Instituto de Energía Solar
  • Departamento: Electrónica Física
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