Preparation of flexible thin films from epitaxially grown anatase Nb: TiO₂ using water-soluble Sr₃Al₂O₆ sacrificial layer

With the aim of developing new electronic functionalities for flexible devices, a transfer process for the preparation of flexible conductive thin films was examined using epitaxially grown anatase Nb: TiO₂. Using pulsed laser deposition (PLD), water-soluble Sr₃Al₂O₆ (SAO) was deposited on a single-crystalline LaAlO₃ (100) substrate (LAO) as a sacrificial layer, followed by the epitaxial growth of anatase Nb: TiO₂ on the sacrificial layer. The Nb: TiO₂/SAO/LAO multilayer sample bonded onto a flexible polymer sheet via an adhesive tape was soaked into distilled water to transfer the epitaxially grown Nb: TiO₂ thin film from SAO/LAO to the polymer sheet. The transferred anatase Nb: TiO₂ thin film retained the clear X-ray diffraction peaks. Moreover, the areal transfer ratio was almost 100%, without the generation of significant impurity phases during the transfer process. On the basis of these results, the examined process was found promising for the preparation of flexible anatase Nb: TiO₂ thin films. The voltage drop–current characteristics were measured successfully at room temperature for the transferred anatase Nb: TiO₂ thin film using the standard four-probe method with gold electrodes.