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XAFS investigation of the local structure of cadmium in Cu(In[subscript 0.7]Ga[subscript 0.3])Se���-based thin films

We have performed fluorescence extended X-ray absorption fine structure
(EXAFS) measurements on the Cd K-edge of partial electrolyte (PE) treated
Cu(In[subscript 0.7]Ga[subscript 0.3])Se��� (CIGS) thin film samples using synchrotron X-ray radiation. This data was compared to the EXAFS spectra of CdSe and CdO standards. Cd local structure
models were constructed and used for the least square analysis of the spectra. The first
model employed implantation of a cadmium atom and a single oxygen atom into the
CIGS lattice. Specifically, an oxygen atom was introduced in the tetrahedral bonded Cd-Se local structure. Employing FEFF8 with WinXAS software package, experimental data
was theoretically fitted to the first shell single-scattering paths of the Cd atom in the (PE)
treated Cu(In[subscript 0.7]Ga[subscript 0.3])Se��� thin film samples. The main peak observed in the data represents the Cd-Se bonds and the shoulder corresponds to the Cd-O bond. However, the number of
total nearest neighbors is not consistent with this model. A two-phase model that includes
both Cd-Se tetrahedron and Cd-O octahedron were then reconstructed. Again, a least-agrees very well with the experimental data, and the total first nearest neighbor number is
consistent with the two phase model at NN=4.2. This study indicates the surface of Cd
partial electrolyte treated Cu(In[subscript 0.7]Ga[subscript 0.3])Se��� thin films contains both CdSe and CdO. / Graduation date: 2004

Identiferoai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/30970
Date10 March 2004
CreatorsMa, Giang N.
ContributorsChang, Chih-hung
Source SetsOregon State University
Languageen_US
Detected LanguageEnglish
TypeThesis/Dissertation

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