Growth behavior of β-Ga2O3 nanomaterials synthesized by catalyst-free thermal evaporation

Various kinds of beta-Ga2O3 nanomaterials such as nanowires, nanorods, nanobelts, nanosheets and nanocolumns have been successfully synthesized by simple evaporation of gallium powder with no assisted catalyst in a flow of argon gas. The as-synthesized materials were pure, structurally uniform, single crystalline with monoclinic beta-Ga2O3 structure (space group: C2 m(-1)) and free from defects. The synthesized nanomaterials were deposited with a growth order of nanocolumn/nanorod, nanowire/nanobelt and nanosheet with synthesis time. The nucleation site was looked over in detail. We present evidence that the surface, edge and tip of previously grown beta-Ga2O3 nanomaterials again provide a nucleation site of new beta-Ga2O3 nanomaterials. Because no metal catalysts were introduced into our growth, a vapor-liquid-solid (VLS) growth is not the likely process in this work, indicating that the observed nanomaterials were grown via a vapor-solid (VS) mechanism.