Although a-Si:H solar cells have great potential in different applications, enhancing their efficiency is still a challenge. An approach to increase the short-circuit current of single junction a-Si:H pin solar cells consists on using mu c-Si:H in the n-layer. In this paper we compare the properties of structures with a-Si:H n-layers and a mu c-Si:H one. We also developed a precise and complete simulation model for further study of the involved electrical variables. For the simulation of the structure with mu c-Si:H a thermionic model must be used. The data was analyzed through the scope of recent findings which highlight the role of conductivity difference in the carrier transport of illuminated solar cells. (C) 2016 Elsevier B.V. All rights reserved.