High Thermoelectric Power Factor and ZT in TbAs:InGaAs Epitaxial Nanocomposite Material

Abstract

Lanthanide monopnictide (Ln-V) nanoparticles embedded within III–V semiconductors, specifically in In 0.53 Ga 0.47 As, are interesting for thermoelectric applications. The electrical conductivity, Seebeck coefficient, and power factor of co-deposited TbAs:InGaAs over the temperature range of 300–700 K are reported. Using Boltzmann transport theory, it is shown that TbAs nanoparticles in InGaAs matrix give rise to an improved Seebeck coefficient due to an increase in scattering, such as ionized impurity scattering. TbAs nanoparticles act as electron donors in the InGaAs matrix while having minimal effects on electron mobility, and maintain high electrical conductivity. There is further evidence that TbAs nanoparticles act as energy dependent electron scattering sites, contributing to an increased Seebeck coefficient at high temperature. These results show that TbAs:InGaAs nanocomposite thinfilms containing low concentrations, specifically 0.78% TbAs:InGaAs, display high electrical conductivity, reduced thermal conductivity, improved Seebeck coefficient, and demonstrated ZT of power factors as high as 7.1 × 10 −3 W K −2 m −1 and ZT as high as 1.6 at 650 K.