1. The problem statement, all variables and given/known data Consider an n-type Si (Eg =1.1eV, ED=EC, εr=11.8) with a bulk doping density ND=1×1017cm-3, a density of acceptor type surface state 1×1014 cm-2 and these states are at the middle of the band gap. Evaluate the amount of: a) band bending b)depletion layer thickness c) density of occupied surface states. 2. Relevant equations Qss=Qsc=eNDd band bending, eVs=e2NDd2/2εrε0 3. The attempt at a solution I attempted to use equation 2 above but there are 2 unknowns in that equation. Not sure what contributes to the Qss=Qsc. Thank you very much!