of energy are either scarce or simply unavailable. The efficiency of a thermoelectric device is essential in determining its practicality and can be assessed using the dimensionless figure of merit ZT 2 S T σ κ = , where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the absolute temperature. Power factor, PF, another commonly used metric for thermoelectric material, is defined by PF = S 2 σ. ZT could be improved by either independently increasing the power factor or reducing the thermal conductivity. However in reality improving the ZT of a material is difficult due to the dependency of various material properties. In most conductive materials, the ratio of thermal conductivity to the electrical conductivity is constant (Wiedemann-Franz law), preventing improvements on ZT by changing either of them. Similarly, increasing the electrical conductivity of a material by means of increasing either carrier concentration or mobility would reduce its Seebeck coefficient, preventing any improvement in PF or ZT.Introducing nanoparticles into a semiconductor matrix can improve ZT by reducing the lattice contribution to thermal 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.

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