Thermal conductivity and specific heat of bulk amorphous chalcogenides Ge20Te80-xSex (x=0,1,2,8)

摘要

Bulk amorphous chalcogenide samples of Ge20Te80-xSex, (x = 0, 1, 2, 8) have been prepared using a melting-quench method, and characterized by the differential scanning calorimetry. X-ray powder diffraction, high-resolution transmission electron microscopy, specific heat and thermal conductivity measurements. The low temperature specific heat measurements identified some localized low-frequency oscillation modes (Einstein modes) in conjunction with a Debye-like behavior. It Was found that with increasing Se concentration the characteristic Debye temperature did not change whereas the Einstein temperature slightly decreased. The lattice thermal conductivity of all Ge20Te80-xSex, samples exhibited typical amorphous| heat conduction behavior, which has been discussed in connection with the phonon mean free path and in the context of a phenomenological model of heat conduction for highly disordered system. (c) 2008 Elsevier B.V. All rights reserved.