the degeneracy factor 𝑣 = 1, the effective mass of the electron 𝑚 𝑒 = 0.045 eV -1 Å -2 s for pristine ML-MoS2 and 𝜇 is the chemical potential. At T = 0 K, 𝜀 F = 𝜇. Hence, we substitute the fitted F values for 𝜇 in Eqn. 2 to calculate 𝑛. We discuss limitations of this zero-temperature approach below. Fig. shows calculated 𝑛 values versus 𝐸. 𝑛 remains low for 𝐸 > +0.50 V. Then, 𝑛 abruptly increases by an order of magnitude over a narrow range (0.30 to 0.50 V). 𝑛 steadily increases with increasingly negative potentials (𝐸 < 0.20 V). For comparison, we also calculated 𝑛 values using the approach of Carroll et. al. , who adapted Wannier-Mott (WM) effective mass theory for 2D quantum wells to calculate 𝑛 for 2D materials (see WM model calculations section in ESI for details). Notably, the WM model does not consider the potentialdependent A -feature and, therefore, the A-exciton region of the absorbance spectrum is fitted with a single component Gaussian. The 𝑛 values in Fig. differ by an order of magnitude but show qualitatively similar behavior. The 𝑛 values calculated from the MND model are likely lower because the approach ignores thermal contributions to 𝑛 and, therefore, likely underestimates the true concentration of conduction band electrons. On the other hand, the 𝑛 values calculated from the Wannier-Mott model sensitively depend on the exciton Bohr radius (𝑛 ∝ 𝑎 0 -2 ), which linearly depends on 𝑚 𝑒 . Varying 𝑎 0