Reactively sputtered TiO2 layers on SnO2:F substrates: A Raman and surface photovoltage study
Date
2008Author
Mwabora, Julius M
Ellmer, K
Belaidi, A
Rappich, J
Bohne, W
Röhrich, J
Dittrich, Th
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
DC reactively sputtered TiO2 layers on SnO2:F substrates were investigated by Raman and surface photovoltage spectroscopy. The
stoichiometry and layer thicknesses were investigated by elastic recoil detection analysis. The deposition temperature, the O2/(O2+Ar) ratio and
the deposition time were varied systematically. With increasing temperature, the layers become crystalline with the rutile modification dominating.
Rutile phase preferentially forms on vertical facets of SnO2 crystallites. Anatase phase starts to form during prolonged deposition and at lower O2/
(O2+Ar) ratios. The energy of the exponential absorption tails below the band gap, a measure of the defect density of the films, is determined by
the deposition temperature and not by other parameters if the deposition temperature is relatively high, irrespective of the content of crystalline
phases or the value of the band gap. Charge separation takes place at length scales significantly shorter than the layer thicknesses (diffusion length
less than 6 nm). TiO2 films sputtered at 380 °C show rectifying behaviour with a carbon contact.
Citation
Thin Solid Films 516 (2008) 3841–3846Publisher
Department of Physics, School of Physical Sciences, University of Nairobi,
Subject
Titanium oxideThin films
Direct current reactive sputtering
Surface photovoltage spectroscopy
Raman spectroscopy
Elastic recoil detection analysis