Growth of self-aligned single-crystal vanadium carbide nanosheets with a controllable thickness on a unique staked metal substrate

Abstract

The single-crystal α-Mo2C nanosheets was first achieved on liquid copper by chemical vapor deposition in 2015. However, the other single-crystal transition-metal carbide nanosheets have not been reported yet. Here, we demonstrate the chemical vapor deposition of single-crystal VC nanosheets with the maximum size of 77 μm on a unique stacked metal substrate. The thickness of VC crystals can be controlled from 12 to 227 nm by changing the deposition pressure (Pd). The reduced Pd decreased the growth rate parallel and perpendicular to the [0 1¯ 1] zone axis. When the Pd was 5000 Pa, the well-aligned single-crystal VC arrays with the thickness of 12 ± 4 nm was obtained. The effect of the hydrogen flow (f) on VC morphology was also discussed. Due to the growth of VC complied to the mass-transport-limited process under high f, the VC crystals tended to be dendrite with the increase of the f. This study could pave a new way for controlling growth of transition-metal carbide nanosheets with tunable thickness and morphology.