Thermoelectric properties of ZnO, CdS, CdSe and ZnS single crystals, theoretical investigation

A theory of thermoelectric power that are affected by a newly modeled phonon drag phenomena in ZnO, CdS, CdSe and ZnS single crystals is proposed. The comparison between the theory and experiments and the analysis of various possible mechanisms of phonon relaxation enabled to conclude that: 1) the phonon drag connects with the piezoelectric interaction between electrons and acoustic phonons; 2) the mechanism of phonon relaxation is the phonon-phonon scattering. Calculations of an anisotropy of the thermoelectric power for a number of compounds have been performed; the anisotropy of a piezoelectric potential and the anisotropy of a phonon spectrum were taken into account. The examined materials can be used in the traditional as well as in the anisotropic thermoelements.