Physics of Semiconductor Devices

pn junction

A silicon pn junction is doped with 10¹⁷ cm^-3 donors on the n-side and 10¹⁷ cm^-3 acceptors on the p-side.

(a) Calculate the Fermi energies on the two sides at 300 K. Set the zero of energy to be at the top of the valence band.

(b) Calculate the built-in voltage for this diode. If you did not find the Fermi energies in part (a), use E_Fn = 1 eV and E_Fp = 0.1 eV.

(c) Draw the electric field as a function of position indicating the direction the field is pointing.

For silicon: E_g = 1.12 eV, N_c = 2.78×10²⁵ m^-3 and N_v = 9.84×10²⁴ m^-3.