  Mott-Schottky analysis is adapted to determine the built-in bias (Vbi) and
doping density (N) of lead sulfide-zinc oxide colloidal quantum dot
heterojunction solar cells. We show that charge injection barriers at the solar
cell's electrodes create a constant capacitance that distorts the junction's
depletion capacitance and result in erroneous Vbi and N values when determined
through Mott-Schottky analysis. The injection barrier capacitance is taken into
account by incorporating a constant capacitance in parallel with the depletion
capacitance.
