Amorphous ZnO-Based Compounds as Thermoelectrics

A Roy and YT Cheng and ML Falk, JOURNAL OF PHYSICAL CHEMISTRY C, 120, 2529-2535 (2016).

DOI: 10.1021/acs.jpcc.5b11618

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 semi-classical 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 similar to 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 parameters are comparable to those known for the state-of-the-art microstructural or nanostructured ZnO.

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