Microstructure scaling of metal-insulator transition properties of VO2 films

Abstract

The metallic to semiconducting resistivity ratios and the transition temperature sharpness of annealed atomic layer deposited VO2 films on amorphous silicon dioxide are found to depend on the grain size in a closely similar way to films from previous sputtered or pulse laser deposited work. This occurs because the dominance of grain growth and compaction processes leads to a common scaling of properties with the grain size. Density functional simulations find that V-V dimerizations allow grain boundaries to remain semiconducting but with a reduced bandgap, while others create metallic grain boundaries, reducing the resistivity ratio for smaller grains in both cases.