Figure 1

Representative pictures of wetting contact angles of (a) HDP-SiO₂ with WCA = 31°, (b) Thermal-SiO₂ with WCA = 45°, (c) PE-Si₃N₄ with WCA = 38° film surfaces and optical microscopy pictures of graphene flakes transferred on corresponding surfaces (d) HDP-SiO₂ (e) Thermal-SiO₂, (f) PE-Si₃N₄.