We present a cross-sectional transmission electron microscopy study of a set of hydrogenated nanocrystalline silicon n-i-p solar cells deposited by hot-wire chemical vapour deposition on Corning glass substrates coated with ZnO-covered Ag layers with various surface roughnesses. Strip-like structural defects (voids and low-density areas) are observed in the silicon layers originating from micro-valleys of Ag grains. A correlation between the opening angles of the textured surface and the appearance of these strips was found. We propose that in order to grow high-quality hydrogenated nano-crystalline silicon absorber layers for solar cell applications. the morphology of the Ag surface is a critical property. and the micro-valleys at the ZnO surface with an opening angle smaller than around 110 degrees should be avoided. (C) 2008 Elsevier B.V. All rights reserved.