Raman-Active Interlayer Phonons and Moiré Phonons in Twisted Thin-Layer MoTe₂

A wide range of artificially twist-stacked van der Waals materials offer versatile building blocks for quantum optoelectronic devices. Among these, twisted bilayer MoTe₂ has excellent optical properties in the near-infrared range and can be integrated with silicon photonics. While recent studies mainly focus on the emission properties in twisted bilayer MoTe₂, a comprehensive investigation of how Moiré superlattice affects phonon modes in twisted thin-layer MoTe₂ remains unexplored. These phonon modes can serve as indicators of stacking configuration and interface uniformity. Here, a series of twisted bilayer and tetralayer MoTe₂ with precisely controlled twist angles ranging from 0° to 60° are prepared. Using polarization-dependent low-frequency Raman spectroscopy, the evolution of interlayer phonon modes at different twist angles is identified. Additionally, a range of acoustic phonon modes activated by Moiré potentials in both twisted bilayer MoTe₂ and twisted tetralayer MoTe₂ are observed and analyzed. The findings provide experimental evidence of the interlayer phonon coupling and Moiré phonons in MoTe₂, offering insights for the future development of near-infrared optoelectronic devices based on twisted thin-layer MoTe₂.