Deposition and characterization of large-scale FePt nanoparticle monolayers on SiO2/Si surface

The deposition of uniform monolayers of FePt nanoparticles on macro-scaled SiO2/Si substrate was demonstrated by employing a simple spin-coating method. The surface morphology and particle density of the monolayers was studied with high resolution scanning electron microscope. FePt nanoparticle monolayers with different morphology were obtained on SiO2 surface at length scales of 1.5 cm. The effects of surfactants, colloid concentration, solvents as well as the shape of the nanoparticles on the uniformity of the particle film were investigated. A primary high temperature annealing on the FePt monolayer films resulted in phase transition from the super-paramagnetic phase into the ferromagnetic one, while the monolayer exhibited limited particle-sintering.