Morphology Optimization of Bi2Se3 Thin Films for Enhanced Thermoelectric Performance

Vapor–solid growth (VSG) is a cost-effective technique to synthesize Bi2Se3 materials with promising thermoelectric (TE) performance. In this work, smooth Bi2Se3 thin films with enhanced TE performance have been realized through regulating the carrier gas flow rate during the VSG process. The optimized morphology improves the electrical conductivity and decouples its interplay withthe Seebeck coefficient in Bi2Se3. As a result, our Bi2Se3 synthesized at 150 sccm gas flow rate exhibited a Seebeck coefficient around −100 μV K–1 and a power factor (PF) of 1.59 × 10–3 W m–1 K–2, which is higher than those of existing thin films and the single-crystal bulk form. This work provides guidance for the controllable preparation of Bi2Se3 thin films with low roughness and high TE performance for potential applications in micro-/nanodevices.