A maskless photolithography technique is provided for the direct synthesis and integration of metallic nanostructures exhibiting branching and flower-like fractal geometries on two-dimensional (2D) carbon-based nanosheets, employing room temperature ultraviolet (UV) irradiation. The photolithography process leverages the structural and electronic properties of carbon-based nanosheets comprising semiconducting organic carbon-based molecular monolayers connected by metallic atoms providing strong covalent linkages. By embedding the metallic precursor for fractal nanostructures within the carbon-based nanosheet during the initial synthesis, UV irradiation initiates the photoreduction of metallic atoms and their growth into fractal nanostructures with high yield and uniformity.