Switchable single c-domain formation in a heteroepitaxial PbTiO3 thin film on a (001) Nb–SrTiO3 substrate fabricated by means of hydrothermal epitaxy

Abstract

We used hydrothermal epitaxy to fabricate a heteroepitaxial PbTiO3 (PTO) thin film on a Nb-doped (001) cubic SrTiO3 (NSTO) substrate while avoiding the phase transition. By means of transmission electron microscopy and piezoresponse force microscopy analyses, it was confirmed that no a domain formed in the heteroepitaxial PTO film; the film had a single +c-domain structure at an as-synthesized state. From the measurement of the polarization-voltage hysteresis curve, large remanent polarization (2Pr:144μC∕cm2) resulting from the single +c-domain structure and an imprint induced by an asymmetric electrode configuration were observed. It is suggested that the single +c-domain structure was caused by the interface of the PTO film and solution rather than the interface of the PTO film and NSTO electrode under the hydrothermal conditions. This hydrothermally synthesized PTO film is anticipated to be very suitable for high-performance engineering applications.

Chemical Solution Deposition of Epitaxial Metal‐Oxide Nanocomposite Thin Films

“…For example, epitaxial perovskite PbTiO 3 films, [41] anatase TiO 2 films, [42] KNbO 3 –NaNbO 3 solid‐solution films, [43] and ZnO films [44] have been hydrothermally synthesized on single‐crystal substrates in the low temperature range of 100–200 °C. This low‐temperature environment can minimize interdiffusion and greatly decrease (or even eliminate) difficulties associated with thermal strain mismatch and other deleterious effects that occur at high temperatures with other epitaxial deposition methods [41e] . Taking lead‐containing films as an example, because of its high vapor pressure, an excess amount of lead is usually required to compensate for its evaporation in a high‐temperature synthesis route [45]…”

“…To grow stoichiometric, homogeneous, high‐quality target films, a systematic study of the process variables (i.e., reagent, concentration, pH value, and temperature) is usually necessary. Properly tuning these variables enables good control over both the reaction and crystallization kinetics [41e] . Thermodynamic model computations are a good way to predict the optimum conditions and even generate equilibrium phase‐yield diagrams for the hydrothermal synthesis of pure phase films [41e] .…”

Preparation of MgO films as buffer layers by laser-ablation at various substrate temperatures

“…Considerable interest is being focused on the development of ferroelectric thin fi lms with perovskite structure for their wide applications in microelectronic and optic-electronic devices, which have been prepared on oxide single-crystal substrates such as MgO, SrTiO 3 or LaAlO 3 etc [1][2][3][4] . However, these substrates are not suitable for device applications since they are expensive and limited to small sizes.…”

Hydrothermally fabricated epitaxial PbTiO3 patterns patterned lithographically by etching in hydrothermal KOH solution

“…Under a certain pressure and temperature ͑ϳ0.5 MPa and 160°C͒, PbTiO 3 film grown by the hydrothermal epitaxy method exhibited good crystal quality with a single +c-domain. 8,9 Earlier, 9 we fabricated a single c-domain structure in heteroepitaxial PbTiO 3 by hydrothermal epitaxy at a temperature ͑=160°C͒. Herein, we report the chemical etching behavior of PbTiO 3 films in KOH solution and discuss the fabrication of nanoscale polarized inverted domains in PbTiO 3 films by scanning probe microscopy ͑SPM͒ based on the electric pulse system technique.…”

“…Details of the fabrication processes can be found elsewhere. 8,9 Morphology of fabricated patterns in the as-synthesized PbTiO 3 film was observed by scanning electron microscopy ͑SEM͒ ͑Philips 3380͒ and atomic force microscopy ͑AFM͒ ͑Seiko SPA 400͒. In order to analyze the nature of nanodomain distribution and the morphology of the PbTiO 3 film surface, the samples were etched using a 6M KOH aqueous solution at an elevated temperature of 150°C in a hydrothermal vessel.…”