Tuning of thermoelectric properties by embedding ErAs nanoparticles in In_(0.53)Ga_(0.47)As crystalline semiconductors

摘要

We theoretically analyzed the thermo electric figure of merit ZT (=S ~2 σT/κ) which can be enhanced by nanostructuring thermoelectric materials. The key reason for increase in ZT is the reduction of thermal conductivity and increase in thermoelectric power by embedding ErAs nanoparticles in In_(0.53)Ga_(0.47)As crystalline semiconductors. The ErAs nanoparticles of mean diameter d = 2.4 nm are randomly distributed in the InGaAs alloy with the concentration of ErAs nanoparticles is 0.3 %. The lattice thermal conductivity and thermoelectric power were studied by incorporating the scattering of phonons with defects, grain boundaries, electrons, and phonons in the model Hamiltonian to evaluate the thermoelectric properties. We found that ErAs nanoparticles provide an additional scatterer to phonons, on inserting the nanoparticles in the crystal the phonon scattering with point defects and grain boundaries become more efficient which cause in decrease the thermal conductivity up to half and increase in thermoelectric power up to double of its value of pure crystal. The temperature- dependent of thermal conductivity and thermoelectric power are determined by competition among the several operating scattering mechanisms for the heat carriers which depends on concentration of nanoparticles in the crystal. Numerical analysis of thermoelectric properties from the present analysis will help in designing better thermoelectric materials for thermoelectric applications.