Fig. 2. Optimization of the n-MoS₂ layer: (a) and (b) donor concentration N_D (cm⁻³), (c) and (d) effective conduction band and valance band density N_C/N_V (cm⁻³), (e) and (f) the bandgap energy E_g (eV), (g) and (h) the number of layers of MoS₂, (i) and (j) the electron affinity χ (eV), and (k) and (l) the dielectric constant ε_r. The p-cSi parameters were maintained as: thickness = 100 μm, N_A = 1 × 10¹⁶ cm⁻³, N_C/N_V = 3 × 10¹⁹ cm⁻³ and χ = 4.05 eV, and the graphene parameters were maintained as: number of layers = 5, reflectance = 0.092 and work function = 4.31 eV. The other parameters are given in Tables 1 and 2.