Low-temperature plasma-assisted growth of germanium nanorods

Abstract

Plasma-assisted growth of germanium nanorods (Ge-NRs) was performed in electron cyclotron resonance (ECR) plasma with a GeH₄–H₂–CF₄ system using indium nanocrystals as seed particles via the vapor–liquid–solid mechanism. The addition of CF₄ was found to be a key factor facilitating low temperature growth of Ge-NRs as it promoted efficient etching of competing surface deposition of Ge, which would lead to the formation of Ge crusts on the surface of indium droplets and thus retard nanorod growth. The effective growth of crystalline Ge-NRs at temperatures as low as 170 °C has been achieved. A systematic study of the diameter dependence of the nanorod growth rate is presented. The growth rate increases with increasing Ge-NR diameter. The results suggest that the direct impingement of growth species on indium liquid droplets is the dominant factor for nanorod growth, indicating that the growth rate is governed by the Gibbs–Thomson effect.