Morphology Optimization of Bi 2 Se 3 Thin Films for Enhanced Thermoelectric Performance

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Vapor–solid growth (VSG) is a cost-effective technique to synthesize Bi 2 Se 3 materials with promising thermoelectric (TE) performance. In this work, smooth Bi 2 Se 3 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 Bi 2 Se 3 . As a result, our Bi 2 Se 3 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 Bi 2 Se 3 thin films with low roughness and high TE performance for potential applications in micro-/nanodevices.