The local atomic structure of CdTe:In at In concentrations of 0, 0.5, and 6
at. % was investigated using x-ray absorption spectroscopy. Changes in the
x-ray-absorption near-edge structure (XANES) and the x-ray-absorption fine
structure (XAFS) were detected for the In K edge. In the In XANES region,
the 0.5 at. % sample exhibits a higher amplitude of the white line than the
6 at. % sample. While in the In K-edge XAFS of both samples only the first
shell contribution is apparent; the environment around In in the 0.5 at. %
sample shows larger disorder than in the 6 at. % In sample. From Cd and Te
XAFS the data exhibit the first three shells of neighbors in agreement wit
h the zinc-blende structure of CdTe, showing increased disorder as a functi
on of In concentration. Results from fits and simulations of both XAFS and
XANES indicate the formation of A centers in the 0.5 at. % sample. For the
6 at. % sample the results indicate a smaller amount of A centers. The poss
ibility of DX center formation is discussed.