Influence of an Al‐Doped ZnO Interface Layer on the Thermochromic Properties of VO 2 Thin Films Deposited by RF Magnetron Sputtering

Vanadium dioxide (VO 2 ) is intensively studied due to its metallic‐to‐insulator phase transition exhibiting thermochromic properties. The deposition of thermochromic VO 2 thin films by magnetron sputtering is strongly dependent on process and substrate parameters. Since transparent and conducting electrodes, such as Al‐doped ZnO, are widely used for optoelectronic applications, it is highly relevant to investigate the growth of VO 2 thin films on this interface layer with glass as the main substrate. Following this aim, the VO 2 deposition on Al‐doped ZnO reveals a faster growth mechanism entailing (020)‐oriented films, in detriment of the typical (011)‐oriented VO 2 observed when grown directly on glass, with a direct impact on the metal‐to‐insulator transition. The annealed VO 2 on Al‐doped ZnO structure is found to exhibit improved recovery of the thermochromic properties with respect to the VO 2 on glass configuration. Furthermore, Zn diffusion into the VO 2 layer, accompanied by an increased transition temperature and a higher sensitivity to the supplied oxygen flow, is observed. It reveals that the Al‐doped ZnO interface layer not only serves as a transparent and conducting electrode but also plays an important role in the functional properties of VO 2 films.