Atomic Migration and Grain Size are Regulated by Pulse Period to Maintain Carrier Concentration and Increase Mobility of Bi₂Te₃ Films

Pulsed electric field (PEF) technology involves the application of current in a periodic form, capable of inducing short-range diffusion or migration in materials through instantaneous changes without causing elemental segregation. In this work, Bi₂Te₃ films underwent PEF treatment with different pulse periods. The pulse period affects the energy transfer of the PEF, thereby regulating the atomic migration rate and increasing the grain size of the material. Bi₂Te₃ films with selected pulse periods exhibit higher carrier mobility (28.02 cm² V⁻¹ s⁻¹) and conductivity (7.58 × 10⁵ S m⁻¹) because of the scattering effect of lower grain boundary density on charge carriers, while maintaining carrier concentration (10²⁰ cm⁻³) and Seebeck coefficient (67.28 μV K⁻¹). When the pulse period is 10 s, the film power factor reaches 4873.33 μW m⁻¹ K⁻² at 513 K. Therefore, this study demonstrates that by altering the pulse period, the microstructure of Bi₂Te₃ films is regulated, leading to an enhancement the thermoelectric (TE) properties.