Chapter 4 - Phonon Blocking Electron Transmitting Superlattice Structures as Advanced Thin Film Thermoelectric Materials

摘要: High figure-of-merit (ZT) thermoelectric materials enable efficient solid-state refrigeration and power conversion. A low-substrate-temperature variant to the conventional MOCVD has been developed for epitaxy of Bi 2 Te 3 —Sb superlattices on GaAs substrates. High-resolution transmission electron microscopy studies indicate that interface between substrate film is qualitatively defect-free periodic structures are formed in superlattices, with one individual layers as small 10A. These apparently have good interfaces, enabling demonstration enhanced carrier mobilities monolayer-range through elimination alloy scattering absence random carriers. The heat transport superlattice offers a scope understanding potential effects related phonon localization phenomena. However, lattice thermal conductivity reduction offered by very useful obtaining high performance materials. chapter provides evidence engineered can attain desirable characteristics phonon-blocking electron-transmitting properties high-performance devices. Detailed based differential ZT measurements well using novel idea relating values ratio at zero electric field current also obtained. It appears intrinsic range 2.5 achievable such blocking transmitting structures.