Nano-crystalline GexC1-x is a potential third generation solar cell absorber material due to its favourable optoelectronic properties and relatively high abundance of elements. The ability to grow nano-crystalline GexC1-x in large areas by an industry-friendly process can enhance its scope as a photovoltaic absorber. In this work nanocrystalline GexC1-x thin films have been grown on Si (100) substrate using radio frequency magnetron sputtering. The crystallinity, composition, structure and optical properties of the films were determined by, Xray photoelectron spectroscopy (XPS), Raman spectroscopy, atomic force microscopy, transmission electron microscopy (TEM) and ultra-violet visible infrared spectroscopy. From TEM results it was found that GexC1-x crystals were scattered in the film with d-spacing of 3.4 nm between the fringes (calculated a = 5.53 angstrom), but that a small number of nanoparticles of GeC were present. The Raman signature of the local Ge-C mode is identified near 530 cm(-1) in GexC1-x film grown at 350 degrees C. The band gap energy value was estimated to be 0.90 eV from optical reflectance spectra. Maximum 15.5% of GexC1-x is found in the film deposited at 350 degrees C using XPS fitting. (C) 2015 Elsevier B.V. All rights reserved.