The effect of microstructure and metal-oxide barriers on carrier transport in top-down processed, low density nanograined n-type PbTe

Abstract

The combined effects of microstructure and interfacial metal-oxide barriers at grain boundaries on carrier transport in top-down processed, nanogranular n-type bulk PbTe have been investigated. It is found that the porous nature of the microstructure leads to significantly reduced thermal conductivity. Naturally occurring metal-oxide potential barriers at the PbTe grain interface result in notably reduced Hall carrier concentration and significantly enhanced resistivity with non-degenerate temperature dependence; they also incorporate additional carrier scattering along with acoustic phonons in the material system. Further, our investigation shows that unlike Hall carrier concentration and resistivity, thermopower is not an inherent property of the bulk granular solid but of its constituent grains.