Covalent Bonding-Based Adhesion Method for Rigidly Coupling Metal Nanocrystals to Metal and Metal Oxide Surfaces

The major challenges of developing a robust strain coupling between nanocrystals and a strain medium are addressed by employing a simple self-assembly-based adhesion process that relies on the formation of metal-oxide bonds between Ni nanocrystals and various surfaces. X-ray photoelectron spectroscopy indicates that the adhesion mechanism necessitates high oxidation potential surfaces capable of metal-oxide bond formation. The process is demonstrated to be reversible, using a reducing plasma to induce adhesion in previously unadhered NiO/Ni nanocrystals. Adhesion to the substrate develops interfacial stress in the nanocrystals resulting in a 40 Oe increase in coercivity and a 25 K shift in the blocking temperature.