Physics of Semiconductor Devices

A silicon pn junction

(a) Draw the band diagram indicating the valence band, the conduction band, the Fermi energy, and the built-in potential, V_bi assuming that no voltage is applied across the junction. Indicate on this diagram approximately where the depletion region would be.

(b) Draw the band diagram in forward and reverse bias.

(c) The doping is N_d = 5×10¹⁵ 1/cm³ and N_a = 1×10¹⁷ 1/cm³. At 300 K, what is the concentration of holes on the p-side and the concentration of holes (minority carriers) on the n-side? For silicon, n_i = 1.5×10¹⁰ 1/cm³.

(d) How could you calculate the depletion width for this diode?