Covalently Bound Gold Nanoparticle-Assisted Epitaxial Growth of Silicon Nanowires

Abstract

Epitaxial growth of one-dimensional nanowires has received considerable attention for vertically aligned nano-electronic devices; however, high integration and reproducibility are still significant problems that need to be addressed. Herein, we investigated the epitaxial growth of silicon nanowires (SiNWs) using covalently bound gold nanoparticles (AuNPs) as catalysts to enhance the lattice matching between the SiNWs and the substrate. We prepared three types of alkene-terminated AuNPs for the formation of covalent bonds between the AuNPs and Si(111) substrates by ligand exchange using alkene-terminated alkanethiols with monodentate ligands (17-octadecenethiol OET and ((4-(undec-10-en-1-yloxy)phenyl)methanethiol UEPMT) and a bidentate ligand (5-(undec-10-en-1-yloxy)-1,3-phenylene)dimethanethiol UEPDT); the immobilization of the AuNPs was achieved by UV irradiation. Finally, we demonstrated a narrow diameter distribution and vertical alignment for the SiNWs covalently bound to the AuNPs in the assisted epitaxial growth and proposed a growth mechanism for the SiNWs using our alkene-terminated AuNPs.