| 초록 |
Since the report of transparent flexible thin-film transistors consisting of oxide materials, the field of flexible oxide devices has been rapidly developed. Because the flexible polymer has low heat-resistive property, the key of the studies is the low growth temperature. In order to reduce the growth temperature, the most conventional study is to explore amorphous materials. On the other hand, one of the most “traditional” applications of the oxide materials has not been examined, i.e., harmonization of the various electronic functions. To realize such application, multilayered epitaxial oxides is required. However, the epitaxial growth of the functional oxides is impossible on the flexible polymer due to its low heat-resistive property. In this study, we propose a process to prepare the epitaxial thin films of dielectric SrTiO3 (STO) and piezoelectric BaTiO3 (BTO) on flexible polymer. An epitaxial STO and BTO thin films were deposited on MgO (100) by pulsed laser deposition. The thin film surface was then bonded to flexible polymer using a direct bonding with oxygen plasma irradiation. The sample was soaked in phosphoric acid aqueous solution to dissolve the MgO. By the process, the epitaxial STO and BTO bonded to the flexible polymer remains. Figure (b) shows the XRD patterns for the STO thin film bonded to flexible polymer material, polyethylene naphthalate (PEN) sheet after etching the MgO substrate. The XRD pattern in Fig. (b) exhibit STO and PEN peaks, but no MgO peaks, meaning we successfully prepared a [100] oriented STO thin film on the flexible PEN sheet. |
