Thermoelectric figure of merit of silicide two-dimensional quantum wells

摘要

The calculation was made to estimate thermoelectric figure of merit ZT of quantum well structured films made of transition metal (TM) silicide, alloys of silicon and germanium, etc. All materials listed (Si/sub 70/Ge/sub 30/, MnSi/sub 2.7/, Ru/sub 2/Si/sub 3/, FeSi/sub 2/, CrSi/sub 2/) are investigated as good thermoelectric materials and furthermore have possibilities of epitaxial growth on silicon. 1-dimensional quantum confinement of charge carrier with quantum well structure were assumed in the calculation model. Transport properties parallel to the layer was estimated as a function of well width. Full account was made of Fermi statistics, and thermal conduction in the barrier layer was taken into account. Results of the calculation indicate that moderate increase in ZT is possible in modulated doping superlattice structure of TM silicides. But ZT decreases with decreasing well width in combinations of silicon and TM silicides. This is due to the large thermal conductivity of silicon used as a barrier material.