研究期間：10108~10207;Due to energy and environment issues, it becomes important to understand the thermal properties of materials. Recently many efforts are to seek efficient thermoelectric materials because there exist potential applications of solid state thermal devices. Several methods were proposed to realize the enhancement of figure of merit (ZT) , one of them is to reduce system dimension such as quantum wells, quantum wires, and quantum dots. However, most of efforts have focused on the electron carriers. To realize thermoelectric devices, we need to consider not only the n-type semiconductors, but also p-type semiconductors for the application of coolers that require the condition of electrically in series and thermally in parallel. As a consequence, it is crucial to clarify the thermoelectric properties of semiconductor with hole carriers in the realization of thermoelectric devices. For electron carriers, parabolic band is employed to describe the relationship between energy and momentum. Nevertheless, a much more complicated band structure beyond parabolic band should be considered for holes due to its p orbital and spin-orbital interaction. In particular, there also exist the strain effect arising from the junction interface to modify the hole p-orbital band structure which yields the flat band with singularity density of states. In the first year, we would like to study thermoelectric properties of a single quantum well system with p-type doping. In the second year, we will consider quantum wires, and then finally . going to study quantum dot superlattices. Hole electrical conductivity, Seebeck coefficient, and hole thermal conductivity are calculated by Boltzmann equation. Lattice thermal conductivity is calculated two fluid model.
