The capabilities of the new method based on the measurement of the diffusion capacitance are explored for the interface characterization of both anisotype and isotype heterojunctions. The influence of interface properties such as interface defect density and band discontinuities on diffusion capacitance is demonstrated. The value of the diffusion capacitance is shown to decrease upon interface defect recombination, whatever the type of the heterointerface (isotype or anisotype). Illustrations are given on two different types of high efficiency heterojunction solar cells, namely a-Si:H/c-Si and AlInP/GaInP solar cells. (c) 2007 Elsevier B.V. All rights reserved.