Catalyst-free growth of graphene on Si substrate using reactive pulsed sputtering

Reactive pulsed plasma sputtering was used to grow graphene directly (i.e., without catalysts) on a Si substrate. Graphene layers and carbon nanowalls were grown at 600 and 800 °C, respectively. Hydrocarbon with sp3-hydrocarbon components, including CHX (X = 1–3), may be the film growth precursors. The amount of precursor supplied by the plasma, which, in turn, governs graphene formation, depends on the target current, as this parameter determines the discharge current. Graphene formation is also attributed to the substrate temperature. Finally, growth time can influence the number of graphene layers, facilitating the growth of few-layer or multilayer graphene.