Well-dispersed monoclinic VO2 nanoclusters with uniform size for sensitive near-infrared detection

As a typical strong correlated material, monoclinic vanadium dioxide (VO2) shows a distinct metal-insulator transition (MIT) near room temperature. The MIT-induced phase separations or other emergent phenomena are closely associated with the grain size and boundaries, especially within nanoscale range. Until now, the pure monoclinic VO2 nanoclusters with uniform grain size and high dispersion have rarely been reported because of the synthesis difficulty and nanocrystal agglomeration. In the current study, we have successfully fabricated well-dispersed monoclinic VO2 nanoclusters with diameters less than 5 nm on various substrates by gas-phase cluster beam deposition. Typical MIT properties including the resistance change and infrared switching effect are observed for the obtained crystal VO2 nanoclusters. In addition, the dispersed VO2 nanoclusters demonstrated excellent infrared response and the response becomes more pronounced as decreasing the spacing of interdigital electrodes, which should be promising for sensitive near-infrared detection. Our current work not only provides a facile way to prepare highly dispersed VO2 nanoclusters with distinct MIT properties but also demonstrates the possible infrared sensing application in the future.