The role of extra carbon source during the pre-annealing stage in the growth of carbon nanofibers

In this letter, we discuss the role of a thin diamond-like carbon (DLC) layer in the growth of carbon nanofibers. We show how the DLC layer acts as an additional carbon source during the pre-annealing stage and changes the nanofiber morphology significantly compared to the case without the DLC layer. Significant amount of carbon is dissolved into the Ni layer during the pre-annealing stage, which leads to supersaturation and subsequent precipitation of carbon out of the Ni particles during the growth stage.