Fig. 4: Exfoliation procedure-dependent MoS₂ dimension.

a Comparison of average estimated exfoliated MoS₂ flake dimensions from AFM image analyses with positive standard deviations representing >100 flakes from several images and image areas. Error bars for layer number in a correspond to 1.4, 2.5, 0.9, and 0.8 for SME, CEPR, RE, and NRE MoS₂, respectively. Error bars for flake lateral size in a correspond to ±61, ±128, ±81, and ±75 for SME, CEPR, RE, and NRE MoS₂, respectively. b Comparison of derived refractive indices, n, at peak A, B, and C exciton energies and at 1000 nm for each MoS₂ film with respect to estimated exfoliated MoS₂ flake layer thicknesses. The layer-dependent n values reported here are compared to those reported by Yu et al. involving dominating excitonic effects (i.e., layer thickness-dependent quantum confinement interplay) and increase in joint density of states (JDOS) with number of layers⁶. Bulk-like properties are generally considered to occur at ≥10 layers.