Effect of plasma excitation frequency and total gas flow rate on the structural properties as well as defect density of nanocrystalline silicon films have been investigated using Raman analysis, Fourier transform infrared spectroscopy, electron spin resonance. It has been found that defect density and microstructural defect in the films are low (1) at higher plasma excitation frequency of 54.24 MHz and (2) at higher total gas flow rate. Defect density and microstructural defect increase as crystallinity of the films increases. Performance of solar cells, prepared with different absorber layers confirm the fact that fill factor and short circuit current increases as defect density decreases. (C) 2008 Elsevier B.V. All rights reserved.