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Growth and surface properties of epitaxial SnO 2
Author(s) -
Rachut Karsten,
Körber Christoph,
Brötz Joachim,
Klein Andreas
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201330367
Subject(s) - x ray photoelectron spectroscopy , epitaxy , low energy electron diffraction , materials science , electron diffraction , analytical chemistry (journal) , ionization , annealing (glass) , photoemission spectroscopy , work function , ionization energy , diffraction , surface states , sputter deposition , stoichiometry , sputtering , thin film , chemistry , nanotechnology , surface (topology) , ion , optics , chemical engineering , layer (electronics) , physics , mathematics , engineering , composite material , geometry , chromatography , organic chemistry
The surface potentials of SnO 2 films grown epitaxially by magnetron sputtering on TiO 2 and Al 2 O 3 substrates with (110), (001), (101), and (100) SnO 2 surface orientations are determined using in situ photoelectron spectroscopy. Epitaxial growth is verified using X‐ray diffraction and low energy electron diffraction. The emphasis lies on the determination of work functions and ionization potentials of epitaxial SnO 2 surfaces. SnO 2 films prepared under chemically reducing conditions exhibit work functions φ of 4.25–4.48 eV and ionization potentials I P of 7.54–8.11 eV. It is furthermore demonstrated that a subsequent annealing in oxygen alters the surface dipole, visible through a large increase of ionization potential. This is due to a change of the surface termination from a reduced to a stoichiometric surface which exhibits Sn in the +IV oxidation state. The observed increase of I P varies from 0.48 eV for the (110) SnO 2 surface to 1.05 eV for the (101) SnO 2 surface.