Chemical vapor deposition of carbon nanotubes on monolayer graphene substrates: Reduced etching via suppressed catalytic hydrogenation using C ₂H₄

In most envisioned applications, the full utilization of a graphene-carbon nanotube (CNT) construct requires maintaining the integrity of the graphene layer during the CNT growth step. In this work, we exhibit an approach toward controlled CNT growth atop graphene substrates where the reaction equilibrium between the source hydrocarbon decomposition and carbon saturation into and precipitation from the catalyst nanoparticles shifts toward CNT growth rather than graphene consumption. By utilizing C₂H₄ feedstock, we demonstrate that the low-temperature growth permissible with this gas suppresses undesirable catalytic hydrogenation and dramatically reduces the etching of the graphene layer to exhibit graphene-CNT hybrids with continuous, undamaged structures.