Assessment of thermoelectric performance of Cu_2ZnSnX_4, X=S, Se, and Te

摘要

A recent experiment on In-doped Cu_2ZnSnSe_4 [X. Y. Shi et al., Appl. Phys. Lett. 94, 122103 (2009)] has shown promising thermoelectric performance characteristics. In this letter, we analyze relevant electronic and transport properties of Cu_2ZnSnSe_4 and similar compounds, Cu_2ZnSnS_4 and Cu_2ZnSnTe_4, to assess their potential as thermoelectric materials. Using density functional theory and Boltzmann transport equations, we determine Seebeck coefficients, conductivities, and power factors of closely related polymorphs with space groups, I4, I42m, and P42w for each compound. Based on their electronic structure and transport properties, we conclude that other two compounds could have similar potential as thermoelectric materials.