Amorphous ZnO-Based Compounds as Thermoelectrics

Abstract

A computational estimate of thermoelectric behavior of amorphous ZnO is reported in this paper. Thermal conductivity of a material is usually lower in an amorphous structure than in a crystalline structure. Most thermoelectrics are based on crystalline semiconductors with the electronic structure optimized to produce a high power factor. Calculations based on density functional theory and semiclassical methods, together with previous experimental results, suggest that the power factor of amorphous ZnO-based compounds could be as high as that of crystalline ZnO. Thermal conductivity of amorphous ZnO is estimated to be only ∼1/25 of that of crystalline ZnO, according to the molecular dynamics calculations presented here. The computed power factor and the lattice thermal conductivity together indicate a figure of merit zT over 0.2 at 600 K for amorphous ZnO. These numbers also suggest that amorphous ZnSnO3 could be a prime candidate to study amorphous thermoelectrics, as its estimated thermoelectric paramete...