Advanced thermoelectric properties in 1D quantum-confined core-shell nanowire heterostructures

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This proposal aims to establish core-shell semiconductor nanowire heterostructures as an experimental platform for advanced nano-thermoelectric materials that exploit several advantages of quantum confinement mediated carrier transport and phonon properties tailored by the core-shell structure. Based on first promising advances made by the applicant, the focus of this project is to explore new types of III-V based core-shell nanowires that simultaneously offer high carrier mobility, strong 1D-confinement with long quasi-ballistic mean free paths of carriers, as well as large atomic mass contrast and structural features that limit thermal transport. Particular attention will be directed towards hitherto unexplored InAs-AlAsSb core-shell nanowires as a new high-mobility lattice-matched 1D n-channel, where key factors governing 1D-transport will be evaluated and enhancements in thermopower related to the 1D-subband structure highlighted. Correlated thermal transport spectroscopy will be performed to evaluate the lattice thermal conductivity minimized by tuning phonon scattering via size effects, alloying and multi-shell interfaces in the core-shell structure. As future functional nano-thermoelectrics require both n- and p-channel devices, we will also apply the methodologies developed for n-type InAs-AlAsSb channels to high-mobility p-type GaSb-AlAsSb channels. The combined efforts on high-mobility n-InAs and p-GaSb channels will further lay important grounds for ambipolar nano-thermoelectrics as well as for future co-integration schemes in Si-based CMOS logic circuits.