Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography

Park, Hyeong‐Ho; Zhang, Xin; Lee, Soon-Won; Jeong, Dong-Joo; Lee, Sang-Moo; Kim, Ki-don; Choi, Dae‐Geun; Choi, Jun-Hyuk; Lee, Jihye; Lee, Eung-Sug; Kang, Hyoungku; Park, Hyung Ho; Hill, Ross H.; Jeong, Jun‐Ho

doi:10.1016/j.mee.2010.12.018

Cited by 13 publications

(4 citation statements)

References 41 publications

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“…Micro- and nanopatterning of metallic or ceramic nanoparticles (NPs) provides opportunities for developing nanomaterial-based electronics, energy devices, sensors, and other types of devices. − Indeed, micro- and nanofabrication and structuring of titanium dioxide NPs has been achieved using various methods including electron-beam lithography, nanoimprint lithography, − electro-hydrodynamic patterning, two-photon lithography, direct-write assembly, ion-beam lithography, and atomic force microscopy (AFM) nanolithography …”

Section: Introductionmentioning

confidence: 99%

UV-Imprint Resists Generated from Polymerizable Ionic Liquids and Titania Nanoparticles

et al. 2014

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Ionic liquids incorporating a polymerizable anion were prepared in a facile manner and used to fabricate stable titania nanoparticle films. The nanotitania was directly patterned by UV imprinting using micrometer size test structures in a polydimethylsiloxane mold. The resulting resist microstructures are resistant to cracking with only slight shrinkage observed for the system made using a hydrophobic ionic liquid. Because ionic liquids with a plethora of different physical and chemical properties can be made (designed) in a facile manner their application in this facile process instead of organic solvents could lead to many new types of functional materials.

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Section: Introductionmentioning

confidence: 99%

UV-Imprint Resists Generated from Polymerizable Ionic Liquids and Titania Nanoparticles

et al. 2014

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“…In fact, the few examples in the literature of direct imprint of inorganic TiO 2 systems reveal that some major challenges have to be faced when working with sol-gel compounds: (1) sol-gel films have high surface energy, causing mold release problems; (2) the solvent or organic moieties (chelating or coordinating agents) that help to 'soften' the material generally get trapped in the imprinted structures; and (3) sol-gel materials do not have a workable softening point, generally exhibiting a thermosetting behavior. As a consequence, inorganic titania patterned films obtained either by thermal (T-NIL) or UV assisted (UV-NIL) imprint, suffer from the following limits: (1) only shallow patterns, less than 100 nm [27,28], can be obtained without crack formation; (2) only films with low titania content can be patterned [23,29,30]; (3) high shrinkages occur during processing up to 75% [31][32][33]; and (4) refractive index up to 1.98 at 632 nm [34] can be achieved only after annealing at 500 °C.…”

Section: Introductionmentioning

confidence: 99%

One-step fabrication of high refractive index inorganic nanostructures

Zanchetta

Giustina

Gandin

et al. 2021

J Sol-Gel Sci Technol

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Direct printing of spin-on functional films is probably the most efficient method to develop low-cost novel photonic nanodevices, such as diffraction gratings, planar waveguides, nano- lasers, and antireflective coatings. For these applications high refractive index transparent materials are demanded; however, this class of materials generally requires inorganic oxides, well known for their hardness, typical of ceramic materials, and so incompatible with a soft character of printable resins. Herein, inorganic high refractive index TiO2 micro- and nano- structures, with unusual depth up to 600 nm and aspect ratio larger than 5, are obtained by combining thermal nanoimprint lithography (NIL) with UV curing. To achieve printed patterns, a hybrid organic-inorganic spin-on film is deposited at low-temperature by sol–gel processing. Two distinct bottom-up synthetic approaches are used, called in situ and ex situ, using titanium isopropoxide (90%) or TiO2 anatase nanoparticles (70%), respectively, and adding a silica sol modified by organic moieties. The two syntheses were optimized to obtain, after patterning by thermal imprint, amorphous or crystalline titania crack-free micro- and nano- patterns for in situ and ex situ, respectively. The further UV irradiation converts imprinted films to totally inorganic patterns, through the titania photocatalytic effect, allowing refractive indexes up to 1.82 at 632 nm to be achieved. This novel strategy of combining thermal imprint with UV exposure allows inorganic deep patterns to be fabricated without a calcination step, which is generally needed for inorganic resists processing. Eventually, a thermal treatment only at 300 °C can be applied to achieve a final refractive index of 2 at 632 nm.

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“…23) Nanoscale imprinting on inorganic materials by the sol-gel method, such as nanopatterning on zinc oxide and titanium oxide layers, has been reported. 24,25) However, the sol-gel method only enables patterning on substrates using limited kinds of materials, and substantial volumetric shrinkage during the heating and drying process, which leads to deformation, is also an issue.…”

Section: Introductionmentioning

confidence: 99%

Formation of ceramic micro-channel by combination of laser beam machining and micro powder imprinting

Tsumori

Hunt

Osada

et al. 2015

Jpn. J. Appl. Phys.

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Microchannels made of polymers are commonly used for MEMS and micro-total analysis system (µTAS) devices. If a micro-channel structure can be constructed of a more stable material, the analysis of more reactant chemicals in harsher environments can be realized. In this research, we developed a process for fabricating a ceramic sheet with micro-channels. The developed process is based on powder metallurgy process. A compound material, a mixture of ceramic powder and polymer, was prepared as the sheet material. We employed laser machining to machine the sacrificial layer to form micro-channels inside the sheet. We also employed imprinting to form a structure with surface patterns and microchannels curving along with it. After the imprinted sheet was debound and sintered by heating, a ceramic sheet with micro-surface patterns and microchannels was obtained.

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Optical characterization of anatase TiO2 films patterned by direct ultraviolet-assisted nanoimprint lithography

Cited by 13 publications

References 41 publications

UV-Imprint Resists Generated from Polymerizable Ionic Liquids and Titania Nanoparticles

UV-Imprint Resists Generated from Polymerizable Ionic Liquids and Titania Nanoparticles

One-step fabrication of high refractive index inorganic nanostructures

Formation of ceramic micro-channel by combination of laser beam machining and micro powder imprinting

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