Figure 3: Si atoms act as catalysts during graphene growth from BLG step-edge.

Some highlighted continuous frames in Supplementary Movie 2, (a–c) and in Supplementary Movie 3, (d–f). The white arrows indicate Si atoms. By comparing the areas inside the dashed circles, new growth of graphene can be clearly seen. The images are taken at 650 °C at a higher frame rate. The cumulative electron doses during beam scanning are: (a) 3.45 × 10⁸ e nm⁻², (b) 3.60 × 10⁸ e nm⁻², (c) 3.75 × 10⁸ e nm⁻², (d) 6.75 × 10⁸ e nm⁻², (e) 6.90 × 10⁸ e nm⁻² and (f) 7.05 × 10⁸ e nm⁻².