Broadband Optical Properties and Band‐Nesting Analysis of Few‐Layer Large‐Area MoS ₂

Broadband transmission spectroscopy measurements are performed to investigate the dielectric properties of few‐layer (4, 6, and 8‐layer) large‐area MoS 2 films and bulk‐like 18 L MoS 2 in conjunction with first‐principles calculations and band‐nesting analysis. In particular, a comparative study is conducted between theory and experiment of the high‐energy peaks in the dielectric function, specifically the C , D , and E peaks observed at 2.8, 3.0, and 4.5 eV, respectively. The analysis shows that the A and B peaks are excitonic, C is a mixture of excitonic and interband transitions, and D and E peaks are entirely due to interband transitions. Band‐nesting analysis reveals several symmetry‐allowed band‐nesting regions within the 2.5–3.0 eV energy range covering the C and D peaks. In contrast, the E peak primarily originates from high‐symmetry Γ → Γ transitions, with little or no enhancement from the band‐nesting effect. Broadly, strong light–matter interactions are demonstrated at the few‐layer level of transition metal dichalcogenides, leading to high dielectric constants.