Thermoelectric properties of p-type PbTe/PbEuTe quantum well structures

We investigate theoretically the thermoelectric properties of (111) oriented p-PbTe/PbEuTe quantum well (QW) structures using a more realistic QW model and the Boltzmann equation approach. The carrier scattering on both optical and acoustical phonons is rigorously taken into consideration. Based on our model we studied the dependencies of Seebeck coefficient, Lorentz number and thermoelectric figure of merit Z_2DT on the well width and hole concentration. It is shown that the presence of twelve Σ valleys in the band structure of p-type PbTe and the decrease of the energy gap between L and Σ valleys due to confinement induced quantization lead to an improvement of the thermoelectric properties. In spite of rather low carrier mobility, the calculated values of Z_2DT exceed those in n-type PbTe/PbEuTe QW´s. The maximum expected values of Z_2DT and the optimal parameters of QWs are determined. The comparison with the experimental data is also presented.