Preparation of [100] oriented SrTiO₃ thin films on flexible polymer sheets

Abstract

In this study, we prepared a uniaxially oriented oxide on a flexible polymer substrate. We first grew [100] oriented SrTiO3 (STO) on a MgO(100) substrate. After bonding the STO film to a poly(ethylene naphthalete) (PEN) sheet with a photoresist, we etched the MgO substrate with a phosphoric acid solution to transfer the oxide film to the PEN sheet. The thin (300 nm) STO films did not crack after release, even after bending the sheet around a rod with a 1 cm radius, while the thicker (800 nm) films did. Ultimately, this process could be adapted to prepare a flexible epitaxial oxide.

Ultrathin Ferroelectric Films: Growth, Characterization, Physics and Applications

“…There are also significant efforts being devoted to transfer (stamp and print by using polydimethylsiloxane (PDMS) stamps or soluble glues) perovskite thin films or nanoribbons onto flexible substrates for the purpose of utilizing the high inherent piezo-properties of ferroelectric materials, or achieving stretchable properties without any loss in ferroelectric/piezoelectric properties [ 32 , 33 , 34 ]. For instance, PZT, BTO, and STO thin films, originally deposited on rigid substrates, have been successfully transferred onto flexible substrates by removing the sacrificial layers such as SiO 2 , MgO and TiO 2 , with the deformation mechanics and material properties being studied [ 32 , 33 , 34 , 35 ].…”

“…In spite of the widely used PDMS substrates, many flexible substrates have been employed into multifunctional flexible circuits based on ferroelectric thin films both organic (like P(VdF-TrFE) [ 36 ]) and inorganic. Some typical examples include polyethylene naphthalate (PEN) [ 35 ], polyethylene terephthalate (PET) [ 37 ], polyimide (PI) substrates [ 38 ], flexible aluminum substrates [ 36 ], and thin glass substrates [ 39 ] etc . However, the limited processing temperature ranges (mostly less than 300 °C) have restrained applications of those plastic substrates in extreme situations such as crystallization process of inorganic ferroelectrics at high annealing temperature, which may result in sophisticated transferring process.…”

Giant Wrinkles on the Surface of Epitaxial BaTiO3 Thin Films with Drastic Shrinkage during Transfer from a MgO(100) Single-Crystal Substrate to a Flexible Polyethylene Terephthalate Sheet

“…We aimed to create flexible oxide engineering of various traditional functional oxides. To achieve this goal, we have investigated the transfer process of epitaxial functional oxide thin films [13,14]. The outline of the transfer process is as follows: the functional oxide is grown on an original substrate that is suitable for epitaxy at a high process temperature, to prepare an epitaxial thin film with good crystallinity.…”

“…In the next step, the thin film of the functional oxide is bonded to a polymer substrate. The epitaxial thin film with the polymer substrate is then released from the original substrate via one of several techniques [13][14][15][16][17][18][19][20][21][22][23][24]. During the process, the epitaxial thin film of the functional oxide is transferred from the original substrate to a polymer substrate.…”

Aggregate ceramic films produced at room temperature by press forming

“…Technologies for transferring single‐crystal thin films deposited by epitaxial growth or high‐temperature‐crystallized films onto plastic substrates have also been advanced . Thin films have been successfully formed using regularly arrayed nanomaterials such as nanosheets and nanocubes, and these thin films have been reported to have novel physical properties such as size‐effect‐free high‐permittivity responses .…”