Low-Temperature Synthesis and Optical Properties of Gel and Ceramic Photonic Crystals Made up of High Dielectric Constant Materials

高介电常数材料凝胶和陶瓷光子晶体的低温合成及光学性能

• 批准号: 12305042
• 负责人: KUWABARA Makoto
• 金额: $ 27.98万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12305042/
• 关键词: 2D Photonic crystal; Sol-gel process; Metal oxides; Resist mold; Photonic band gap; Optical reflection property; Low-temperature synthesis; 低温合成; セラミックフォトニック結晶; チタニア; チタン酸バリウム; 金属アルコキシド; ドライエッチング; フォトニック結晶; ゾルーキャスティング法; 電子線描画法; 高屈折率透明ゲル

The objective of this study is to establish a low temperature synthesis method for fabricating two-dimensional TiO_2 and BaTiO_3 gel and ceramic photonic crystals by sol-gel processing using resist molds and also to evaluate the optical properties of the obtained crystals.The obtained results are summarized as follows:1) Synthesis of precursor sol solutions : We prepared a TiO_2 precursor solution by mixing titanium isopropoxide, Ti(O-i-Pr)_4, poly(ethylene glycol) (PEG: molar weight=400), ethylene glycol monomethyl ether (EGMME) as a solvent and water for hydrolysis of the alkoxide to have the composition Ti(O-i-Pr)_4: EGMME : H_2O = 1:3:1 (in molar ratio), and also prepared a BaTiO_3 precursor solution by using the same procedure with barium ethoxide, Ba(OC_2H_5)_2. These precursor solutions gave crack-free gel films of the respective materials when spin-coated on Si and MgO substrates.2)Preparation of resist molds : We first prepared resist films of around 1μm by spin coating on Si … More and MgO substrates, and then formed hexagonal arrays of air holes with various values of air holes radius r and spacing between holes (lattice constant) a in the resist alms using electron beam lithography. The values of r and a of the resist molds produced were theoretically determined from photonic band structure calculations to allow the photonic crystals to be fabricated exhibit complete photonic band gaps in the visible region.3)Fabrication of TO_2 and BaTiO_3 gel photonic crystals : We succeeded in fabricating two-dimensional photonic crystals consisting of hexagonal arrays of TiO_2 and BaTiO_3 precursor pillars on Si and MgO substrates, respectively, by casting the precursor sol solutions into the resist molds, drying, then followed by removing the resist molds chemically with a removal agent Prior to the removal of resist molds it is necessary to remove completely a gal film that the present method unavadably form on the resist mold, and we succeeded in ding it with a dry etching technique using CF_4/C_3F_8 gas.4) Fabrication of TiO_2 and BaTiO_3 ceramic photonic crystals : TiO_2 and BaTiO_3 ceramic photonic crystals were obtained by sintering the precursor get photonic crystals at temperatures of 500 to 800℃ in air. The obtained photonic crystals showed no appreciable lattice disorder of the crystals, with little collapse of the precursorpillars, though significant changes in the size of the pillars due to their shrinkage during firing were observed5) Evaluation of optical properties of the obtained photonic crystals : Optical reflection measurements in the wavelength range of 400 to 1000nm were carried out for TiO_2 ceramic photonic crystals with different rand a values of (r=110nm, a=400nm), (125nm, 450nm) and (125nm, 500nm) and for a BaTiO_3 ceramic photonic crystal with a=450nm and rl=0.19 in the Γ-Mand f-Kdrections of the crystals for both TE and TM modes, in which distinct reflection peaks were observed for all the photonic crystals at around wavelengths calculated. The results dearly demonstrate that 2D ceramic photonic crystals with wall-developed photonic band gaps in the optical regime have been successfully fabricated for the first time in this study. Less

本论文的主要目的是建立一种利用溶胶-凝胶法制备二维TiO_2和BaTiO_3凝胶光子晶体和陶瓷光子晶体的低温合成方法，并对所制备的光子晶体的光学性能进行评价，主要研究结果如下：1）前驱体溶胶溶液的合成：以异丙醇钛、Ti（O-i-Pr）_4、聚偏二氟乙烯、聚偏二氟乙烯为原料，（乙二醇）（PEG：摩尔量=400）、乙二醇单甲醚（EGMME）作为溶剂和水用于水解醇盐以具有组成Ti（O-i-Pr）_4：EGMME：H_2O = 1：3：1（摩尔比），并与乙醇钡Ba（OC_2H_5）_2按相同的方法制备了BaTiO_3前驱体溶液。这些前体溶液在Si和MgO衬底上旋涂时得到相应材料的无裂纹凝胶膜。2）抗蚀剂模具的制备：我们首先通过旋涂在Si上制备约1μm的抗蚀剂膜 ...更多信息 和MgO衬底，然后使用电子束光刻在抗蚀剂Alms中形成具有各种空气孔半径r和孔之间的间距（晶格常数）a的空气孔的六边形阵列。通过光子能带结构计算，确定了制备的抗蚀剂模的r和a值，使制备的光子晶体在可见光区具有完全的光子带隙。3）TO_2和BaTiO_3凝胶光子晶体的制备：我们成功地制备了由TiO_2和BaTiO_2六角阵列组成的二维光子晶体。通过将前体溶胶溶液浇铸到抗蚀剂模具中，干燥，然后接着用去除剂化学去除抗蚀剂模具，分别在Si和MgO衬底上形成3个前体柱。在去除抗蚀剂模具之前，必须完全去除本方法不可避免地形成在抗蚀剂模具上的gal膜，4）TiO_2和BaTiO_3陶瓷光子晶体的制备：在500 ~ 800℃的温度下，将TiO_2和BaTiO_3陶瓷光子晶体在空气中烧结，得到TiO_2和BaTiO_3陶瓷光子晶体。所获得的光子晶体没有显示出可察觉的晶体晶格无序，并且几乎没有柱体的塌陷，尽管由于柱体在烧制期间的收缩而导致的柱体尺寸的显著变化被忽略。在400 ~ 1000 nm波长范围内，对不同兰德a值的TiO_2陶瓷光子晶体进行了光反射测量（r= 110 nm，a= 400 nm），（125 nm，450 nm）和（125 nm，500 nm）三种波长的光子晶体，以及a= 450 nm，rl=0.19的BaTiO_3陶瓷光子晶体，在TE和TM模式下，在晶体的Γ-M和f-K方向上都观察到明显的反射峰。结果表明，在本研究中首次成功地制备了具有光学带隙的二维陶瓷光子晶体。少

项目成果

桑原 誠: "透明な機能性セラミックス"まてりあ. 39・2. 79-83 (2000)

桑原诚：“透明功能陶瓷”Materia 39・2（2000）。

S.Shimada, K.Miyazawa, M.Kuwabara: "An Easy Method for Fabricating TiO_2 Gel Photonic Crystals Using Molds and Highly Concentrated Alkoxide Solutions"Japan.J.Appl.Phys.. 41. L291-L293 (2002)

S.Shimada、K.Miyazawa、M.Kuwabara：“使用模具和高浓度醇盐溶液制造 TiO_2 凝胶光子晶体的简单方法”Japan.J.Appl.Phys.. 41. L291-L293 (2002)

S.Shimada, M.Matsuu, K.Miyazawa, M.Kuwabara: "Fabrication of Two-Dimensional Gel Photonic Crystals by Sol-Gel Method Using High Concentration of Alkoxide Solution"J.Ceram.Soc.Jpn. 110. 391-394 (2002)

S.Shimada、M.Matsuu、K.Miyazawa、M.Kuwabara：“使用高浓度醇盐溶液通过溶胶-凝胶法制造二维凝胶光子晶体”J.Ceram.Soc.Jpn。

K.Hamamoto, M.Kuwabara: "Effect of Electric-Field-Induced Polarization on Positive Temperature Coefficient of Resistivity Characteristics of Semiconducting Barium Titanate Ceramics"Jpn. J. Appl. Phys.. 40. L1163-1165 (2001)

K.Hamamoto，M.Kuwabara：“电场感应极化对半导体钛酸钡陶瓷电阻率特性正温度系数的影响”Jpn。

S.Shimada, M.Matsuu, K.Miyazawa, M.Kuwabara: "Fabrication of Two-Dimensional BGel Photonic Crystals by Sol-Gel Method Using High Concentration of Alkoxide Solution"J.Ceram.Soc.Japan. 110. 391-394 (2002)

S.Shimada、M.Matsuu、K.Miyazawa、M.Kuwabara：“使用高浓度醇盐溶液通过溶胶-凝胶法制备二维 BGel 光子晶体”J.Ceram.Soc.Japan。