Microscopic Theory of Thermoelectric Properties of Silicon Nanowires

摘要

We present predictions of the thermoelectric figure of merit (ZT) of Si nanowires, as obtained using Boltzman transport equation and ab-initio electronic structure calculations. We find that ZT is strongly dependent on the nanowire growth direction and surface reconstruction and we discuss general rules to select silicon based nanostructures with combined n-type and p-type optimal ZT. In particular, our calculations indicate that 1 nm wires grown in the (001) and (011) directions can attain ZT values which are about twice as high as those of ordinary thermoelectric materials. In this Letter, we report on atomistic calculations of the thermoelectric figure of merit of silicon nanowires (SiNW), a prototypical, nanostructured material for thermoelectric applications. A combination of Molecular Dynamics (MD) simulations, Density Functional Theory (DFT) structural and electronic calculations, and Boltzmann Transport Equation (BTE) simulations are used to provide a microscopic theory of thermoelectric properties of silicon nanowires and to predict hand to predict how to design silicon based materials with improved ZT.