Systematic study and performance optimization of transparent conducting indium–zinc oxides thin films

To optimize the physical properties of In2O3–ZnO pulsed laser deposited thin films, we embarked on a systematic study of their microstructural characterization and transport properties. We found that the electrical properties of the films are greatly governed by their microstructure, which evolves from granular to fiber and to columnar textures, as we go from cubic In2O3 to hexagonal ZnO via ZnkIn2Ok+3 layered structure in the binary In2O3–ZnO phase diagram. Maximum conductivity is reached for a Zn/(Zn+In)=0.5 (at.) composition having a layered ZnkIn2Ok+3-type structure with essentially k=2, which was synthesized for the first time. Electrochemical measurements show that this film can be used as a transparent electrode in electrochromic devices operating either in an aqueous or organic medium.