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 Zn_kIn₂O_{k + 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 Zn_kIn₂O_{k + 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.