Direct low-temperature deposition of graphene on an insulator via hydrogen-assisted sputtering

In this study, the direct growth of graphene on insulating substrates was performed at low temperatures (500–700 °C) using hydrogen-assisted sputter deposition with an Ar/H2 gas mixture and a graphite target. Using this approach, few-layer {002}-oriented graphene was formed on SiO2/Si substrates without the use of catalysts or transfer processes. The resulting film exhibited an electrical conductivity of 123 S cm−1 (sheet resistance of 4.07 × 104 Ω/□), hole mobility of 24.5 cm2 V−1 s−1, and carrier concentration of 3.14 × 1019 cm−3. By systematically varying the substrate temperature and hydrogen gas fraction, four distinct regions were identified, corresponding to graphene growth, carbon nanowalls, amorphous carbon, and no film deposition. The study findings suggested that the generation of CHx species by chemical sputtering of the graphite target played an important role in graphene growth, and that the growth mechanism was governed by the balance between the surface decomposition of CHx on the heated substrate and the hydrogen-induced etching of unstable carbon atoms. This approach therefore represents a simple and scalable route for transfer-free graphene integration on insulators at reduced temperatures.