(30 pоints) Cоnsider аn intrinsic semicоnductor аt temperаture T. In thermal equilibrium, the electron and hole concentrations are n₀ and p₀, respectively. Assume the nondegenerate limit so that Boltzmann statistics apply.When the semiconductor is uniformly illuminated, it reaches a steady nonequilibrium state with electron and hole quasi-Fermi levels E_Fn and E_Fp, and carrier concentrations n and p. Assume that E_g, N_c, and N_v are known.1. Derive an expression for the product np in terms of the quasi-Fermi levels.2. Draw a schematic band diagram showing the positions of the two quasi-Fermi levels under light illumination. 3, When the light is turned off and the semiconductor returns to equilibrium, derive the product of the electron and hole concentrations in terms of E_g, T, N_c, and N_v.