Plasma low-energy ion flux induced vertical graphene synthesis

Vertical graphene (VG) is a promising material for energy-storage, sensor, and electronic applications, owing to excellent structural, mechanical, and electrical properties. An existing method for synthesizing VG is plasmaenhanced chemical vapor deposition under high plasma ion-energy interaction on carbon surface. However, since this method can cause substrate damage, device performance degradation, and internal defects in VG, a new synthesis method using low-ion-energy is required. Accordingly, it is necessary to understand how the plasma low-ion energy contributes to the nucleation and growth of VG by interaction with the surface, but the reported studies are limited to the high-ion-energy region. Here, we report on the effects of low-energy ion flux in plasma-induced growth of vertical graphene and found the key plasma parameter for the VG growth and nucleation in a low-ion-energy environment and successfully controlled the nucleation of VG. VG deposition and plasma parameter measurements were performed in a radiofrequency inductively coupled plasma. In the lowenergy region, the growth rate and nucleation of VG depended strongly on ion density, and insufficient ion flux formed highly disordered carbon. Based on these findings, VG nucleation was controlled by tailoring the ion energy and density under conditions where disordered carbon was formed.