EXAFS study of the temperature dependence of the Debye–Waller factor in ZnSe zincblende compound

Abstract

In this work, we investigate the temperature dependence of the Debye–Waller (DW) factor in a zincblende-type ZnSe crystal. For this purpose, we measured the extended x-ray absorption fine structure spectra at the Zn and Se K edges in the temperature range of 20–573 K. The DW factor can be described by two different models namely Einstein correlated model and Debye correlated model. The parallel and perpendicular DW factors, the Einstein parameters and Debye temperature are determined and discussed. The temperature dependence of the DW factor of the first, second and third bond distances corresponding to each edge are presented and discussed in terms of vibrational motion. The Einstein frequencies are compared to the vibrational densities of states. The vibrational motion of the first and second coordination shells are affected by the vibrational modes below the energy of the transverse optic modes and around the energy of the transverse acoustic modes, respectively. The DW factor extracted for each shell is influenced by different parts of the phonon spectrum.