Nanostructure Formation from Polycrystalline Vanadium Dioxide Films Using an Atomic Force Microscope

Vanadium dioxide (VO
2
) is a functional material of great practical interest due to its unique reversible first order metal-insulator phase transition behavior. This transition is accompanied by a structural phase transition that causes dramatic changes in electrical, optical properties and lattice deformation. Recently, an active search for new methods of forming VO
2
nanostructures has been going on. Such nanostructures generally exhibit more pronounced phase transition properties and, due to their sizes, are highly stable against mechanical deformation that arise during the structural phase transition. A method of nanostructuring polycrystalline VO
2
films using scanning probe nanolithography is discussed for the first time. Current research is aimed to the surface modification of VO
2
films when a positive voltage is applied to the samples. The impact of the applied voltage value, duration, and atmospheric humidity on the nanolithographic patterns quality were investigated. The reaction mechanisms were analyzed. It is found that the oxide structures composed of V
2
P
5
after local anodic oxidation are completely dissolved in water. Therefore, the solid polycrystalline VO
2
film is decomposed into individual nanostructures with exactly predetermined dimensions. The described technique is a promising direction to form nanostructures from crystalline VO
2
films for novel nanophotonics and nanoelectronics.