High Resolution X-ray photoemission
study of plasma oxidation of In-Sn-Oxides thin film surfaces
Dr R Egdell
The electro luminescent devices are based
upon the movement of electrons between the cathode to anode
via LUMO to HOMO transitions with excess energy being emitted
as light.
Two anode materials are considered:
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Sn1-xSbxO2
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In2-xSnxO3
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Dr
R Egdell |
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The doping is required in order to populate the Sn 5s or
In 5s states in the anode materials. New phosphor materials
based on Lanthanide ions in an organo-metallic matrix have
been developed, which need to be matched to the anode materials.
This can be achieved by plasma treating the ITO anode. The
treatment dramatically improves the performance of the coatings,
but why?
XPS analysis of the O1s line before and
after plasma treatment suggests that the BE of the line
moves to a lower energy, possibly due to the formation of
new surface species (J.Appl.Phys. 2000). Using the Scienta
at Daresbury is was possible to accurately see the changes
in the O1s line and also shifts in the work function of
the plasma treated material.
HREELS measurements on Sn doped In2O3 show
changes in the plasmon structure. Similar effects may be
seen in the plasmon structure in the core lines in the XPS
spectra. In this instance these are intrinsic plasmons,
are superimposed on the main core lines, causing peak broadening
and slight shifts in the peak position.
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