In this work. we have investigated the difference and the potentiality of amorphous crystalline silicon (c-Si) heterojunctions based on both n-type and p-type c-Si substrate. Experimental comparison of solar cell performances realized on different doping type crystalline wafer have been evaluated and discussed. We have analyzed with the aid of a numerical model, useful for multilayer structure description, the transport mechanism and the influence of interface defect density on the behavior of both kind of solar cell heterostructures. Differences in the technological steps needed to device formation have been considered for high efficiency solar cell. Finally, an explanation of the difference in the role played by the defect density at the interface for both kind of structure has been proposed. (C) 2003 Elsevier B.V. All rights reserved.