Tailoring In2Ga2ZnO7 thin film properties by annealing time effect

Highlights: • Crystallization of In₂Ga₂ZnO₇ film took place at minimum of 5 min annealing at 500 °C in room ambient. • Amount of oxygen vacancy decreased as annealing temperature increased causing changes in energy bandgap indirect transition. • Interfacial layer formed on underlying substrate when annealed for 60 min. • Incorporation of interfacial layer increased leakage current of IGZO film. Properties of indium gallium zinc oxide (In₂Ga₂ZnO₇) thin films on silicon (Si) substrate prepared using sol-gel method in response to annealing time were thoroughly studied. Post-annealing treatment for 5, 15, 30 and 60 min has revealed changes on surface morphologies, film roughness, film thickness and optical energy bandgap. InGaZnO (IGZO) structure was determined to be polycrystalline after annealing at 500 °C temperature regardless of annealing time. The increase in annealing time to 60 min successfully encouraged the formation of interfacial layer (IL) on the underlying Si substrate, owing to a build-up of oxygen molecules diffused from the ambient that resided in the lattice. As a result, a larger leakage current was obtained from leakage current density-voltage (J-V) characteristic. Corresponding properties of the films in comparison to 60 min annealing were further elaborated in terms of optical and electrical characterization.