Effect of sequential grafting of magnetic nanoparticles onto metallic and semiconducting carbon-nanotube devices: towards self-assembled multi-dots

We demonstrate that van der Waals interactions can be used to self-assemble a small, controlled number of magnetic nanoparticles onto metallic and semiconducting carbon nanotubes. We study the effect of the sequential grafting on the room temperature transport properties of carbon-nanotube electronic devices containing metallic or semiconducting carbon nanotubes. The results show that the grafting of the nano-objects has different effects on metallic and semiconducting CNTs, with an appreciable effect for single nanoparticle grafting only on field effect transistors. The results indicate that these grafting techniques are suited for the production of multi-quantum dot systems usable at low temperatures. Magnetization measurements of single nano-objects using carbon nanotube-based magnetic sensors, like nano-SQUID devices, also become feasible.