Carrier pocket engineering to design superior thermoelectric materials using GaAs/AlAs superlatices

摘要

A large enhancement in the thermoelectric figure of merit for the whole superlattice, Z_(3D)T, is predicted for short period GaAs/AlAs superlattices relative to builk GaAs. Various superlattice parameters (superlattice growth direction, superlattice period and layer thicknesses) are explored to optimize Z_(3D)T, including quantum wells formed at various high symmetry points in the Brillouin zone. The highest room temperature Z_(3D)T obtained in the present calculation is 0.41 at the optimum carrier conentration for either (001) or (111) oriented GaAs(20 A)/AlAs(20 A) superlattices, which is bout 50 times greater than the corresponding ZT for bulk GaAs obtained using the same basic model.