The inter-metallic oxide of ZnO/ITO/ZnO tri-layer films using a heat-induced diffusion mechanism

► The study presents the interface diffusion behavior based on ZnO/In/ZnO and ZnO/ITO/ZnO tri-layer films. ► The heat-induced thermal diffusion caused an intense inter-metallic oxide (IMO) in the interface and a doping layer. ► IMO and doping layer that enhanced the electrical conductivity. ► The formation of IMO and good contact behavior can also improve the film transmittance.