The solar cells using silicon technology have been modeled and fabricated reaching 19% cell efficiency in the past. In an effort to maximize efficiency and reduce cost to reach the grid parity, thin films of silicon are being investigated. In this study, a solar cell hetero-junction with an intrinsic thin layer (HIT) was simulated on a p-type substrate, which can be manufactured with standard silicon manufacturing processes. The influence of different parameters such as the temperature, the back surface field, different layer thicknesses, different doping concentrations for p and n type layers, ZnO and ITO as transparent conductive oxides with plane and texturized surface shapes and densities of interface defects (D-it) on the efficiency was investigated. For simulation of hetero-structures, AFORS-HET software was used in the study. Our results indicate that by optimizing different parameters of hetero-structure thin films, a high performance can be obtained using nanostructured surfaces up to an efficiency of 25% for HIT silicon solar cells. Optimized design parameters for HIT silicon solar cell for fabrication are proposed. (C) 2013 Elsevier Ltd. All rights reserved.