Figure 2.

Optical characterization of MoS₂/Cu at various annealing temperatures. a) Refractive index, n(ω), and b) extinction coefficient, k(ω), of MoS₂/Cu annealed at various temperatures and MoS₂/Al₂O₃ measured by high‐resolution spectroscopic ellipsometry. The inset is the schematic band structure of 1T′‐MoS₂. The lattice distortion along with strong electron–electron correlations in 1T′‐MoS₂ results in a band inversion around Γ‐point, which lowers the W d‐orbital below the Se p‐orbital and opens an inverted gap. c) Comparing Raman spectra of MoS₂/Cu before and after annealing at 150, 250, and 300 °C. d) Annealing temperature dependent of photoluminescence spectroscopic results.