Control of iron nanoparticle size by manipulating PEG-ethanol colloidal solutions and spin-coating parameters for the growth of single-walled carbon nanotubes

► Iron nanoparticles were prepared on silicon wafers via spin-coating colloidal solution. ► The smallest and most uniform iron catalyst particles were selected for CCVD. ► The effects of various operating parameters were studied. ► Single-walled CNTs with high selectivity were synthesized.