Functionalization of ITO thin films for VO2 based thermochromic devices

ITO thin films are the most commonly used transparent conductors in a wide variety of devices. However, in their fully optimized state the ITO films are not compatible with other types of devices exhibiting optical change in the near infrared region. One such class are the thermochromic devices based on vanadium dioxide (VO2) thin films. The VO2 films exhibit a very effective optical modulation in the near infrared region where the ITO films are not transparent. The aim of the present work is to functionalize the ITO films and to render them compatible for use with the VO2 based thermochromic devices. The thickness dependence of the optical and electrical properties of these functionalized ITO films is also studied. The dependence of the electrical properties on film thickness has been examined in the light of the existing size effect theories for the first time. Near-infrared transparent ITO films with adequate electrical properties have been achieved for the required application.