Anisotropy in thermal and electronic properties of single crystal GeSe 2 obtained by the photoacoustic method

Abstract

Anisotropy in the thermal and electronic properties for two directions of a thermal wave propagation in GeSe 2 single crystal was investigated using the photoacoustic frequency transmission technique. First, the electric field of an incident polarized light beam was adjusted to be perpendicular to the "c" axis (E 1 ⊥ c), and then parallel to it (E 1 //c). It is shown that there is an obvious difference in the PA amplitude and phase spectra of the same sample, for cases when E 1 //c and E 1 ⊥ c axis. The results for thermal diffusivity D T obtained by fitting procedure for these two orientations of the electric field with regard to the "c" axis, are calculated: D T // = 1.1 × 10 -2 and D T ⊥ = 1.7 × 10 -3 cm 2 /s, e.g. their ratio is 6.6. The electronic transport parameters are also given: the carrier ambipolar diffusion coefficient D// = 1.5 cm 2 /s and D⊥ = 2.5 cm 2 /s.