Ruthenium oxide (RuO2) thin films have been prepared using single step chemical method containing Ru(III) Cl-3 solution in an aqueous medium at low temperature. The structural, morphological and optical properties have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and optical absorption technique. The XRD study revealed the formation of amorphous RuO2 thin film. The surface examination by SEM showed formation of nano-porous material on the substrate. The TEM study revealed the formation of nanostructured material. The optical absorption studies showed the presence of direct band transition with band gap equal to 2.2 eV. The RuO2 has proved its applicability in supercapacitor showing 50 F/g specific capacitance in 0.5 M H2SO4 at 20 mV/s scan rate. (c) 2007 Elsevier B.V. All rights reserved.