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

Cd_1-xZn_xTe crystal is a new kind of room temperature semiconductor radiation detector material developed in recent years. Cd_1-xZn_xTe is zinc-blende structure, which is similar to CdTe, but the fine structure of Cd_1-xZn_xTe ternary compound semiconductor is different from CdTe and ZnTe binary compound semiconductors. In this contribution, the fine structure of Cd_1-xZn_xTe 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 Cd_1-xZn_xTe 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 Cd_1-xZn_xTe have also been obtained by extended X-ray absorption fine structure (EXAFS), and the results imply that the local atomic structure of Cd_1-xZn_xTe is distorted. The doping of Zn in the structure contributes to the distortion, which should be responsible for the different properties in Cd_1-xZn_xTe. Normalized X-ray absorption near-edge structure (XANES) spectra on Cd K-edge, Zn K-edge and Te K-edge in CdTe, Cd_0.96Zn_0.04Te, Cd_0.9Zn_0.1Te and ZnTe are also shown.