A modified Butler-Volmer model is developed to predict the potential of perfect stoichiometry (PPS) for electrodeposition. CdTe thin films are deposited in an acidic solution: their electrodeposition mechanism is investigated using cyclic voltammetry. Calculated and experimental PPS values exhibit good agreement. At PPS, well-connected granular CdTe thin films can be deposited; these are predicted to be intrinsic, and slightly p-type due to cadmium vacancies. Type conversion occurs only because of defect redistribution and local defect reactions after annealing; the converted n-type layer exhibits lower resistivity and higher mobility. A film annealed at 350 degrees C exhibits excellent crystallization. (C) 2009 Published by Elsevier B.V.