Growth of carbon nanotubes on Si/SiO2 wafer etched by hydrofluoric acid under different etching durations

► Etching Si/SiO2 wafer with 48-50% HF generates SiO2 nanoparticles. ► Metal-catalyst-free growth of CNTs on SiO2 nanoparticles is demonstrated. ► TEM shows the presence of SWCNTs on Si/SiO2 wafer etched at 1 min after CVD.