XAFS and XRD Studies of the Cd1-xZnxTe Crystal Fine Structure

Cd1−xZnxTe crystal is a new kind of room temperature semiconductor radiation detector material developed in recent years. Cd1−xZnxTe is zinc-blende structure, which is similar to CdTe, but the fine structure of Cd1−xZnxTe ternary compound semiconductor is different from CdTe and ZnTe binary compound semiconductors. In this contribution, the fine structure of Cd1−xZnxTe has been studied by the synchrotron radiation X-ray absorption fine structure (XAFS) technology and X-ray diffraction (XRD) technology. The K-edges XAFS spectra of cadmium, zinc and tellurium in Cd1−xZnxTe have been obtained, and the differences between the structures of binary and ternary compound crystals have also been analyzed. The Fourier transform of the k2-weighted absorption spectra prove that Zn atoms occupy the position of the Cd atoms. The bond lengths of Cd1−xZnxTe have also been obtained by extended X-ray absorption fine structure (EXAFS), and the results imply that the local atomic structure of Cd1−xZnxTe is distorted. The doping of Zn in the structure contributes to the distortion, which should be responsible for the different properties in Cd1−xZnxTe. Normalized X-ray absorption near-edge structure (XANES) spectra on Cd K-edge, Zn K-edge and Te K-edge in CdTe, Cd0.96Zn0.04Te, Cd0.9Zn0.1Te and ZnTe are also shown.