Thermoelectricproperties of p-typePbTe/PbEuTe quantum well structures

I.Sur¹, A.Casian¹, A.A. Balandin², Z. Dashevsky³

¹Departmentof Computers, Informatics and Microelectronics, Technical University ofMoldova, Chisinau, MD 2004, Moldova

²Nano-DeviceLaboratory, Department of Electrical Engineering, University of California -Riverside, Riverside, California 92521 USA

³Departmentof Materials Engineering, Ben-Gurion University, Beer-Sheva, 84105 Israel

We have carried outtheoretical investigation of the thermoelectric properties of (111) oriented p-PbTe/PbEuTe quantum well (QW)structures using the realistic QW model and Boltzmann equation approach. Thecarrier scattering on both optical and acoustical phonons is rigorouslyincluded into consideration. Based on our model we studied the dependencies ofthe power factor, thermal conductivity and thermoelectric figure of merit ZT on the well widthand hole concentration. It is shown that the presence of twelve Σ valleysin the band structure of p-type PbTe and the decrease ofthe energy gap between L and S valleys due to confinement inducedquantization lead to an improvement of the thermoelectric properties. In spiteof rather low carrier mobility the calculated values of the power factor and ZTexceed those in n-type PbTe/PbEuTe QW’s.The maximum expected values of ZT and the optimal parameters of QW’s aredetermined. The comparison with the experimental data is also presented.