Lattice thermal conductivity of nanostructured thermoelectric materials based on PbTe

Abstract

We report the through-thickness lattice thermal conductivity l of (PbTe) 1-x / (PbSe) x nanodot superlattices (NDSLs) over a wide range of periods 5 nmh50 nm, compositions 0.15x0.25, growth temperatures 550 K Tg 620 K, and growth rates 1 μm h-1 R4 μm h-1. All of our measurements approach l of bulk homogenous PbTe1-x Sex alloys with the same average composition. For 5 nmh50 nm, l is independent of h; a result we attribute to short mean-free paths of phonons in PbTe and small acoustic impedance mismatch between PbTe/PbSe. We alloyed the PbTe layers of four NDSLs with SnTe up to a mole fraction y=18%; l is reduced by <25%. © 2009 American Institute of Physics.