TiO₂ thin film crystallization temperature lowered by Cu-induced solid phase crystallization

We lowered the crystallization temperature of amorphous TiO₂ thin films using a Cu catalyst as either a bottom or cap layer. The Cu bottom layer reduced the crystallization temperature of TiO₂ by ~ 30 C. Depth profile analyses by Rutherford backscattering spectrometry revealed that a very small amount of Cu was sufficient to induce full crystallization of the TiO₂ film. Depositing the Cu cap layer and annealing at 210 C for 3 h yielded a transparent anatase TiO₂ thin film upon wet-etching the Cu cap.