Single and Multiple‐Step Dip‐Coating of Colloidal Maghemite (γ‐Fe2O3) Nanoparticles onto Si, Si3N4, and SiO2 Substrates

Abstract

AbstractThe adsorption behavior of colloidal maghemite (γ‐Fe2O3) nanoparticles, passivated by oleic acid and dispersed in octane solution, onto three different substrates (Si, Si3N4, and SiO2) is investigated. The average nanoparticle size is 10 nm, with a size variation (σ) less than 5 %. The adsorption of particles is strongly dependent on both the type of substrate and the particle concentration in solution. By a single‐dipping process, we have obtained a maximum coverage of 0.45 on a Si substrate, but much less on other substrates (0.19 on Si3N4 and 0.14 on SiO2). The particle coverage was drastically increased by the multiple‐adsorption process, where the process of dipping and drying was repeated multiple times. With this process, we can obtain a maximum particle coverage of about 0.76 on a Si substrate and 0.61 on a thermally grown SiO2 substrate.