ZnO nanostructures were grown on carbon fabric with and without a capping agent using a simple hydrothermal method, and the growth times were varied in order to study the effect of the capping agent. The formation of ZnO wurtzite nanostructures was observed from the structural analysis of the sample with a capping agent. Morphological and mapping analyses observed the varied morphology of the capping agent over the different growth times. The interaction between the carbon fabric and the grown ZnO nanostructures was then studied via elemental analysis, and the strongest C–O–Zn bond was observed for the capping agent sample with the highest growth time. The formation of OH − ions induced when the growth time increased resulted in the formation (Zn 2+ ) of densely grown ZnO nanostructures and improved stability was obtained via TGA analysis. The maximum thermopower calculated is + 5.9 μV K −1 , and all the samples exhibited p-type in nature.