Consider a slab of GaAs with Np = 1017 cm. (a) A surface donor 0.5 eV below the conduction band is introduced. How does (Ec EF) at the surface change as the density of these donors is increased from 1010 cm2 to 1014 cm. (b) Repeat the above problem, but with an acceptor state (at the same energy level) instead of a donor state. (c) Now, assume that the acceptor state is 0.3 eV below Ec and the donor state is 0.5 eV below Ec. The density of these states is kept equal and increased from from 1010 cm2 to 1014 cm. How does (Ec Ef) at the surface change? (d) Now, the positions of donor and acceptor are interchanged. The donor state is 0.3 eV below Ec and the acceptor is 0.5 eV below Ec. Again, plot (Ec Ef) at the surface of the density is kept equal and increased from 1010 cm2 to 1014 cm?. Consider a slab of GaAs with Np = 1017 cm. (a) A surface donor 0.5 eV below the conduction band is introduced. How does (Ec EF) at the surface change as the density of these donors is increased from 1010 cm2 to 1014 cm. (b) Repeat the above problem, but with an acceptor state (at the same energy level) instead of a donor state. (c) Now, assume that the acceptor state is 0.3 eV below Ec and the donor state is 0.5 eV below Ec. The density of these states is kept equal and increased from from 1010 cm2 to 1014 cm. How does (Ec Ef) at the surface change? (d) Now, the positions of donor and acceptor are interchanged. The donor state is 0.3 eV below Ec and the acceptor is 0.5 eV below Ec. Again, plot (Ec Ef) at the surface of the density is kept equal and increased from 1010 cm2 to 1014 cm