We observe >6% efficiency enhancement in silicon thin film solar cell using a p-type microcrystalline silicon oxide (mu c-SiO:H) contact layer between transparent conducting oxide (TCO) electrode and the hydrogenated amorphous silicon (a-Si: H) layer. The role of the above contact layer is to reduce the Schottky barrier effect as well as the hetero-junction barrier formation at the interface. Despite its nanometer scale thickness, the properties of the contact layer significantly affect the solar parameters. Based on our results, p-type doped mu c-SiO:H can be an ideal material as a contact layer due to its good optical response without noticeable degradation in its electrical property. (C) 2013 Elsevier B.V. All rights reserved.