Mechanically-exfoliated stacks of thin films of Bi2Te3 topological insulators with enhanced thermoelectric performance

摘要

The authors report on “graphene-like” mechanical exfoliation of single-crystal Bi2Te3 films andnthermoelectric characterization of the stacks of such films. Thermal conductivity of the resultingn“pseudosuperlattices” was measured by the “hot disk” and “laser flash” techniques. The roomntemperature in-plane u0002cross-planeu0003 thermal conductivity of the stacks decreases by a factor of u00042.4nu00023.5u0003 as compared to bulk. The thermal conductivity reduction with preserved electrical propertiesnleads to strong increase in the thermoelectric figure of merit. It is suggested that the film thinningnto few-quintuples and tuning of the Fermi level can help in achieving the topological-insulatornsurface transport regime with an extraordinary thermoelectric efficiency.