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In situ photoemission from semiconducting WO3 electrodes
A435 Surface Science @ North-Holland
101 (1980) 155-161 Publishing Company
IN SITU PHOTOEMISSION FROM SEMICONDUCTING WOs ELECTRODES l M.A. BUTLER Sandia
Laboratories
Received
l*, Albuquerque,
27 September
New Mexico 87185, USA
1979; accepted
for publication
10 December
1979
Both anodic and cathodic photocurrents have been observed from illuminated WOr electrodes and their dependences on electrode potential and incident photon energy have been explored. With the semiconductor/electrolyte junction biased into accumulation, anodic photocurrents are observed with a threshold equal to the band gap of WO, and independent of potential. As the potential is made more negative, the shape of the spectral response curve changes and at -0.6 V (SCE) the photocurrent changes sign. This effect is reversible and shows hysteresis. At slightly more positive potentials interference between anodic and cathodic photocurrents is observed. The hysteresis and change in color of the electrode suggests growth of d H,W03 layer on the surface and electron emission from this layer. The threshold for electron emission shifts linearly with potential and agrees with the threshold observed for electron emission from metals. The electron emission from H,WO, shows structure in the spectral response.
Surface Science @ North-Holland
101 (1980) 162-172 Publishing Company
PHOTOCURRENT SPECTROSCOPY OF LEAD DIOXIDE L.M. PETER Department Received
of Chemistry, 15 October
The University,
Southampton
SO9 5NH,
UK
1979
Lead dioxide is a degenerate n-type semiconductor which behaves almost as a metal. When PbOr is reduced, however, the stoichiometry changes and a semiconducting phase with a much lower free electron density is formed. The deposition of PbOr on a platinum anode has been followed by interferometry, and the subsequent reduction of the film has been characterized by photocurrent spectroscopy. The latter technique has given information about the band gap and stoichiometry of the lower oxides of lead formed during the reduction of PbOz. The mechanism of photocurrent generation and a simple model which takes account of the semiconducting properties of the lead oxides will be discussed.
101 (1980) 155-161 Publishing Company
IN SITU PHOTOEMISSION FROM SEMICONDUCTING WOs ELECTRODES l M.A. BUTLER Sandia
Laboratories
Received
l*, Albuquerque,
27 September
New Mexico 87185, USA
1979; accepted
for publication
10 December
1979
Both anodic and cathodic photocurrents have been observed from illuminated WOr electrodes and their dependences on electrode potential and incident photon energy have been explored. With the semiconductor/electrolyte junction biased into accumulation, anodic photocurrents are observed with a threshold equal to the band gap of WO, and independent of potential. As the potential is made more negative, the shape of the spectral response curve changes and at -0.6 V (SCE) the photocurrent changes sign. This effect is reversible and shows hysteresis. At slightly more positive potentials interference between anodic and cathodic photocurrents is observed. The hysteresis and change in color of the electrode suggests growth of d H,W03 layer on the surface and electron emission from this layer. The threshold for electron emission shifts linearly with potential and agrees with the threshold observed for electron emission from metals. The electron emission from H,WO, shows structure in the spectral response.
Surface Science @ North-Holland
101 (1980) 162-172 Publishing Company
PHOTOCURRENT SPECTROSCOPY OF LEAD DIOXIDE L.M. PETER Department Received
of Chemistry, 15 October
The University,
Southampton
SO9 5NH,
UK
1979
Lead dioxide is a degenerate n-type semiconductor which behaves almost as a metal. When PbOr is reduced, however, the stoichiometry changes and a semiconducting phase with a much lower free electron density is formed. The deposition of PbOr on a platinum anode has been followed by interferometry, and the subsequent reduction of the film has been characterized by photocurrent spectroscopy. The latter technique has given information about the band gap and stoichiometry of the lower oxides of lead formed during the reduction of PbOz. The mechanism of photocurrent generation and a simple model which takes account of the semiconducting properties of the lead oxides will be discussed.