Enhancing Thermoelectric Properties of 2D Bi₂Se₃ by 1D Texturing with Graphene

Two-dimensional (2D) thermoelectrics have shown enhanced performance compared to bulk thermoelectrics but cannot easily be improved through nanostructuring, since phonon-boundary-scattering becomes ineffective under confined dimensions. To overcome this issue, we introduce a one-dimensional (1D) texturing approach that efficiently suppresses phonon transport between grains of 2D thermoelectrics (TE). Uniaxial graphene wrinkles were utilized to separate high-quality, ultrathin Bi2Se3 films in a highly directional manner. The TE properties of these textured samples exhibit a strongly anisotropic characteristic with a maximum ZT of 1.03 at room temperature, which represents the highest reported value for Bi2Se3. The texturing approach provides a route for the enhancement of 2D thermoelectrics for future applications.