• 정보저장시스템학회논문집
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• 제3권1호
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• pp.43-46
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• 2007

The fabrication of metal nanostructures by a combination of atomic force microscopy nanomachining on a thin polymer resist, metal coating and lift-off is reported. Nanodots with sizes and nanowires with widths ranging between 50 and 100 nm have been successfully created. The present work exemplifies the feasibility and effectiveness of using a single-layer resist in comparison with a two-layer resist. In addition, the localized surface plasmon resonance peaks of the metal nanostructures have been measured and the selective growths of zinc oxide nanowires on the metal nanostructures are demonstrated.

• 대한금속재료학회지
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• 제49권4호
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• pp.342-347
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• 2011

We fabricated the silicon nanodots using the low pressure chemical vapor deposition technique to investigate their electron field emission characteristics. Atomic force microscope measurements performed for the silicon nanodot samples having various process parameters, such as, deposition time and deposition pressure, revealed that the silicon nanodots with an average size of 20 nm, height of 5 nm, and density of $1.3\;{\times}\;10^{11}\;cm^{-2}$ were easily formed. Electron field emission measurements were performed with the silicon nanodot layer as the cathode electrode. The current-voltage curves revealed that the threshold electric field was as low as $8.3\;V/{\mu}m$ and the field enhancement factor reached as large as 698, which is compatible with the silicon cathode tips fabricated by other techniques. These electron field emission results point to the possibility of using a silicon-based light source for display devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.9-10
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• 2005

We report on the fabrication and characterization of self- and artificially-controlled ZnO nanostructures have been investigated to establish nanostructure blocks for ZnO-based nanoscale device application. Systematic realization of self- and artificially-controlled ZnO nanostructures on $SiO_2/Si$ substrates was proposed and successfully demonstrated utilizing metalorganic chemical vapor deposition (MOCVD) in addition with a focused ion beam (FIB) technique. Widely well-aligned two-dimensional ZnO nanodot arrays ($4{\sim}10^4$ nanodots of 130-nm diameter and 9-nm height over $150{\sim}150{\mu}m^2$ with a period of 750 nm) have been realized by MOCVD on $SiO_2/Si$ substrates patterned by FIB. A low-magnification FIB nanopatterning mode allowed the periodical nanopatterning of the substrates over a large area in a short processing time. Ga atoms incorporated into the surface areas of FIB-patterned nanoholes during FIB engraving were found to play an important role in the artificial control of ZnO, resulting in the production of ZnO nanodot arrays on the FIB-nanopatterned areas. The nanodots evolved into dot clusters and rods with increasing MOCVD growth time.

• Macromolecular Research
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• 제16권2호
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• pp.103-107
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• 2008

Carbon nanodots were prepared by the pyrolysis of a triblock copolymer. The triblock copolymer, poly(methyl methacrylate)-b-polystyrene-b-poly(methyl methacrylate) was synthesized by atom transfer radical polymerization using an initiator containing a diacetylene group. A polymer thin film on a mica substrate was prepared by spin-casting at 2,000 rpm from a 0.5 wt% toluene solution of the triblock copolymer. After drying, the cast film was vacuum-annealed for 48 h at $160^{\circ}C$. The annealed film formed a spherical morphology of polystyrene domains with a diameter of approximately 30 nm. The film was exposed to UV irradiation to induce a cross-linking reaction between diacetylene groups. In the subsequent pyrolysis at $800^{\circ}C$, the cross-linked polystyrene spheres were carbonized and the poly(methyl methacrylate) matrix was eliminated, resulting in carbon nanodots deposited on a substrate with a diameter of approximately 5 mn.

• 한국자기학회지
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• 제17권3호
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• pp.137-140
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• 2007

레이저 간섭 석판 장비(Laser Interference Lithography; LIL)를 이용하여, Anodic Aluminum Oxide(AAO) 나노기공의 배열을 향상 시켰다. 이후 진공에서 Fe와 Cu를 AAO/Si에 성장하고, AAO를 제거하여 Cu/Fe(20 nm) 나노구조를 제작하였다. AAO의 나노기공과 나노구조는 전처리 과정에서 제작된 PR(photoresist) 나노선을 따라 1차원으로 배열되었다. 자성 나노구조의 자기이력곡선으로부터 이들이 vortex 구조를 가지며, 쌍극자 상호작용이 지배적임을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제10권2호
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• pp.12-15
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• 2008

Nano-sized dots have been formed on the buffered metal substrates using the novel approach of the electro-spray deposition, to modulate the substrate surface and induce the columnar defects in REBCO films grown on it. The $BaZrO_3$ precursor solution was synthesized and electro-sprayed out onto the negatively charged substrate surface. Using the electrostatic force, nano-sized dots can be grown and uniformly distributed on the buffered metal substrate. The height of BZO nanodots was observed above the 200nm, which are beneficial to induce the columnar defects onto the BZO as a seed. The density of BZO nanodots was also investigated and ${\sim}7.8/{\mu}m^2$ was obtained. As the deposition distance of electro-spray was shortened there was ${\sim}8times$ increase of density of nanodots. The optimization of process variables in electro-spray deposition are discussed in respect to the superconducting REBCO films processed by the Metal-Organic Deposition with the effective flux pinning properties.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.36.2-36.2
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• 2008

• Journal of Magnetics
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• 제13권2호
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• pp.53-56
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• 2008

This study proposes a simple nano-patterning process for the fabrication of magnetic nanodot arrays on a large area substrate. Ni nanodots were fabricated on a large area (4 inches in diameter) Si substrate using the soft lithographic technique using self-assembled surface micelles of Polystyrene-block-Poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer formed at the air/water interface as a mask. The hexagonal array of micelles was successfully transferred to a Ni thin film on a Si substrate using the Langmuir-Blodgett technique. After ion-mill dry etching, a magnetic Ni nanodot array with a regular hexagon array structure was obtained. The Ni nanodot array showed in-plane easy axis magnetization and typical soft magnetic properties.

• Journal of Magnetics
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• 제10권2호
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• pp.58-62
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• 2005

Periodic magnetic nanodot arrays were successfully produced on glass substrates by interference laser lithography and electron beam lithography methods. Magnetic force microscopy (MFM) observation was carried out on fabricated nanodot arrays. MFM tip induced magnetization effects were clearly observed in ferromagnetic elliptical nanodots varying in material and aspect ratio. Fe-Cr dots with a high aspect ratio show reversible switching of the single domain magnetization state. At the same time, Co nanomagnets with a low aspect ratio exhibit tip induced transitions between the single domain and the vortex state of magnetization. The simple nanolithography is potentially an efficient method for fabrication of patterned magnetic arrays.

• 한국결정성장학회지
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• 제16권1호
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• pp.12-19
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• 2006

Metalorganic chemical vapor deposition (MOCYD) techniques have been applied to fabricate semiconducting ZnO thin films and nanostructures, which are promising for novel optoelectronic device applications using their unique multifunctional properties. The growth and characterization of ZnO thin films on Si and $SiO_2$ substrates by MOCYD as fundamental study to realize ZnO nanostructures was carried out. The precise control of initial nucleation processes was found to be a key issue for realizing high quality epitaxial layers on the substrates. In addition, fabrication and characterization of ZnO nanodots with low-dimensional characteristics have been investigated to establish nanostructure blocks for ZnO-based nanoscale device application. Systematic realization of self- and artificially-controlled ZnO nanodots on $SiO_2/Si$ substrates was proposed and successfully demonstrated utilizing MOCYD in addition with a focused ion beam technique.