Study on the Fabrication of Ferroelectric Ultrathin Films and Nanostructures by MOCVD and Their Size Effects

MOCVD铁电超薄膜和纳米结构的制备及其尺寸效应研究

• 批准号: 17360144
• 负责人: SHIMIZU Masaru
• 金额: $ 4.54万
• 依托单位: University of Hyogo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360144/
• 关键词: Size Effect; PbTiO_3 Ultrathin Films; PbTiO_3 Nanoislands; MOCVD; Piezoresponse Force Microscopy; Critical Thickness; Phase Transition Temperature; Synchrotron X-Ray Diffraction; 強誘電体極薄膜; 強誘電体ナノ構造; 強誘電体; 極薄膜; ナノ構造; 自己集合化

In order to investigate the size effect in ferroelectric thin films and nanoisland structures, PbTiO_3 ultrathin films and nanosilands were fabricated by MOCVD and their structureal nature and ferroelectric properties were studied.1) Epitaxial PbTiO_3 ultrathin films with thicknesses of 10-0.9nm were successfully grown on SrRuO_3/SrTiO_3 by MOCVD.2) Piezoresponse measurements using Piezoresponse Force Microscopy (PFM) and observation of ferroelectric polarization using scanning nonlinear dielectric microscopy (SNDM) evidently proved the presence of ferroelectricity in PbTiO_3 ultrathin films with a thickness of 1.3nm (3 mono layers (ML)). Ferroelectrcity was not observed in the 0.9nm (2.2 ML) -thick film. In our experiment, critical thickness was 1.3nm.3) PbTiO_3 and PZT nanoislands were successfully fabricated on Pt/SrTiO_3 substrates by self-assembly using MOCVD. Three types of islands (pyramidal-shaped, triangular-prism-shaped and square-shaped islands) were grown on Pt/SrTiO_3(111), (110) and (001), respectively.4) PFM measurement proved the presence of ferroelectrcity in the PbTiO_3 nanoisland with a width of 27nm and a height of 1.2nm.5) Phase transition temperatures of PbTiO_3 nanoislands on Pt/SrTiO_3(111) and (110) were measured by Raman spectroscopy. From Raman measurement, it was fond that phase transition temperatures in pyramidal-shaped islands and triangular-prism-shaped islands decreased as island size decreased.6) Crystal structure of the nanosiland on Pt/SrTiO_3(111) was investigated using Synchrotron X-ray diffraction. As island size decreased, the c-axis lattice constant decreased at sizes smaller than 100nm though the a-axis lattice constant did not changed.7) Nano-sized Au dots were successfully fabricated by self-assembly. Using these Au nanodots as a top electrode, I-V characteristics of PbTiO_3 nanosilands on Pt/SrTiO_3 were measured.

为了研究铁电薄膜和纳米兰州结构的尺寸效果，MOCVD制造了PBTIO_3超层膜和纳米层的尺寸效果，并研究了其结构性和铁电特性。1）pbtio_3超层膜，具有10-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-SR的超级膜，SR通过MOCVD.2）使用压电响应力显微镜（PFM）进行了压电测量，并使用扫描非线性介电显微镜（SNDM）观察铁电性极化，这显然证明了PBTIO_3超级膜中的铁电性的存在，其厚度为1.3nm（3 mono）。在0.9nm（2.2 mL）厚膜中未观察到铁电性。在我们的实验中，临界厚度为1.3nm.3）PBTIO_3，PZT纳米群岛通过使用MOCVD自组装在PT/SRTIO_3底物上成功制造。在pt/srtio_3（111），（110），（110）和（001）上生长了三种类型的岛屿（锥形形状，三角形 - 形状和方形的岛屿）。Pfm测量证明了在PBTIO_3 Nanois lods中的三个nanois thermmy thermmy thermite thermmy firept thermite thermmy fireph thermmy the nannois fordthe the nannois thermmy firept the nannois the nannnn nan and the nan and and and and and and nan nan and and and nanno shos的27NM和27N，通过拉曼光谱法测量了pt/srtio_3（111）和（110）上的pbtio_3纳米群岛。从拉曼测量中，人们对锥形岛的相过渡温度和三角形晶体形岛的岛屿的尺寸降低。6）纳米岛的晶体结构在PT/SRTIO_3（111）上使用Synchrotrotron X射线差异进行了研究。随着岛屿尺寸的减小，尽管A轴晶格常数没有变化，但小于100nm的C轴晶格常数下降。7）纳米尺寸的AU点已通过自动构造成功制造。使用这些AU纳米型作为顶电极，测量了PBTIO_3纳米硅在PT/SRTIO_3上的I-V特性。

项目成果

Fabrication of Self-Assembled Au Nanodots and Their Applications to Ferroelectric Nanocapacitors

自组装金纳米点的制备及其在铁电纳米电容器中的应用

• 发表时间: 2006
• 期刊: Jpn. J. Appl. Phys. 45
• 作者: Eiji Higurashi;Yuichiro Tokuda;Masatake Akaike;and Tadatomo Suga;清水 勝;M.Shimizu;H.Fujisawa et al.;清水 勝;H.Fujisawa
• 通讯作者: H.Fujisawa

Microstructure and Ferroelectric Properties of Ultrathin PbTiO_3 Films by MOCVD

MOCVD超薄PbTiO_3薄膜的微观结构和铁电性能

• 发表时间: 2006
• 期刊: Materials Research Society Symposium Proceedings 902E
• 作者: H.Fujisawa et al.;H.Fujisawa et al.;H.Fujisawa et al.;清水 勝 他;Hironori Fujisawa
• 通讯作者: Hironori Fujisawa

Fabrication of Self-Assembled Au Nanodots and Their Applications to Ferrolelectric Nanocapacitors

自组装金纳米点的制备及其在铁电纳米电容器中的应用

• 发表时间: 2006
• 期刊: Jpn. J. Appl. Phys. 45
• 作者: Eiji Higurashi;Yuichiro Tokuda;Masatake Akaike;and Tadatomo Suga;清水 勝;M.Shimizu;H.Fujisawa et al.;清水 勝;H.Fujisawa;H.Fujisawa;H.Fujisawa;H.Fujisawa et al.
• 通讯作者: H.Fujisawa et al.

Fabrication of Ferroelectric Nanostructures and Their Properties

铁电纳米结构的制备及其性能

• 发表时间: 2007
• 期刊: Ceramics Japan 42
• 作者: Eiji Higurashi;Yuichiro Tokuda;Masatake Akaike;and Tadatomo Suga;清水 勝;M.Shimizu
• 通讯作者: M.Shimizu

Fabrication of Ir-based Electrodes by Metalorganic Chemical Vapor Deposition

金属有机化学气相沉积法制备铱基电极

• 发表时间: 2006
• 期刊: Jpn. J. Appl. Phys. 45
• 作者: Eiji Higurashi;Yuichiro Tokuda;Masatake Akaike;and Tadatomo Suga;清水 勝;M.Shimizu;H.Fujisawa et al.;清水 勝;H.Fujisawa;H.Fujisawa;H.Fujisawa;H.Fujisawa et al.;H.Fujisawa et al.
• 通讯作者: H.Fujisawa et al.