Manipulating metal-insulator transitions of VO2 films via embedding Ag nanonet arrays*

Manipulating metal-insulator transitions in strongly correlated materials is of great importance in condensed matter physics, with implications for both fundamental science and technology. Vanadium dioxide (VO2), as an ideal model system, is metallic at high temperatures and shown a typical metal-insulator structural phase transition at341 K from rutile structure to monoclinic structure. This behavior has been absorbed tons of attention for years. However, how to control this phase transition is still challenging and little studied. Here we demonstrated that to control the Ag nanonet arrays (NAs) in monoclinic VO2(M) could be effective to adjust this metal-insulator transition. With the increase of Ag NAs volume fraction by reducing the template spheres size, the transition temperature (T (c)) decreased from 68 degrees C to 51 degrees C. The mechanism of T (c) decrease was revealed as: the carrier density increases through the increase of Ag NAs volume fraction, and more free electrons injected into the VO2 films induced greater absorption energy at the internal nanometal-semiconductor junction. These results supply a new strategy to control the metal-insulator transitions in VO2, which must be instructive for the other strongly correlated materials and important for applications.

Automated summary

Controlling the Ag nanonet arrays in monoclinic VO2(M) can effectively adjust the metal-insulator transition, with the transition temperature (T (c)) decreasing from 68 degrees C to 51 degrees C as the volume fraction of Ag NAs increases. The mechanism of the T (c) decrease involves an increase in carrier density through the introduction of more free electrons into the VO2 films at the metal-semiconductor junction. These findings offer a new strategy for controlling metal-insulator transitions in VO2 and have potential implications for other strongly correlated materials and their applications.