Figure 3. Strong, layer-dependent excitonic effects in atomically thin MoS₂ films.

(a) The position of the C peak in MoS₂ films as a function of the thickness of the film L. The error bar ± 0.005 eV results from the possible errors in determining the peak position. The dashed lines are the fitting results using the model of infinite quantum wells (fitting 1) and the quantum well in fraction space (fitting 2) (b) The position of the C peak in MoS₂ films as a function of 1/L², where L is the thickness of the film. The red line is the fitting results using the model of infinite quantum well with the fitting equation given as shown. The inset is a magnified version of the area indicated by the dashed yellow rectangle. (c) The dependence of the binding energy and exciton radius in MoS₂ films on the layer number.