• Applied Microscopy
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• v.48 no.2
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• pp.43-48
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• 2018

Transition metal dichalcogenide (TMD) materials have distinctive structures in comparison with other two-dimensional materials. TMD materials' structure is held together by van der Waals and covalent intralayer interactions; consequently, TMDs exhibit multiple phases and properties depending on their structure. This article reviews some of the research currently being undertaken to control TMD phases to utilize their different properties. This review introduces some trials for changing the phase of TMDs.

• Applied Microscopy
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• v.44 no.4
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• pp.123-132
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• 2014

Silicene is one of the most interesting two-dimensional materials, because of not only the extraordinary properties similar to graphene, but also easy compatibility with existing silicon-based devices. However, non-existing graphitic-like structure on silicon and unstable free-standing silicene structure leads to difficulty in commercialization of this material. Therefore, substrates are essential for silicene, which affects various properties of silicene and supporting unstable structure. For maintaining outstanding properties of silicene, van der Waals bonding between silicene and substrate is essential because strong interaction, such as silicene with metal, breaks the band structure of silicene. Therefore, we review the stability of silicene on other two-dimensional materials for van der Waals bonding. In addition, the properties of silicene are reviewed for silicene-based heterostructure.

• International Journal of Internet, Broadcasting and Communication
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• v.4 no.1
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• pp.1-2
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• 2012

A speaker is a system which produces sound through electromechanical operations. It transforms electronic signals into audible sound signals. Almost all speakers are three dimensional. These days, many mobile electronic devices such as mobile electronic devices have become smaller and thinner. A problem with this miniaturization, however, is that the volume of speakers has also decreased. In contrast to conventional three dimensional speakers, we have invented a new type of two dimensional flexible speaker by utilizing the reverse piezoelectric effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.1-10
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• 2022

Two-dimensional materials have shown a great promise for the next-generation electronic materials due to their unique optical, physical, and chemical properties that are distinct from their bulk counterparts. Their atomic-level thickness, the feature for flexible tenability, and exposed huge surface allow various approaches for high-performance nanoscale devices. Especially, this review highlights the recent progress on two-dimensional dielectric nanosheets, which are obtained by cheap and massproducible solution-based exfoliation process, accompanied by the preparation methods, various deposition methods, and the characteristics of devices using a dielectric nanosheet thin films. We also present a perspective on the advantages offered by this two-dimensional dielectric nanosheets for the upcoming future nanoelectonics.

• Transactions on Electrical and Electronic Materials
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• v.5 no.1
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• pp.34-37
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• 2004

Amorphous chalcogenide thin films, especially a-(Se, S) based films, exhibit a number of photo-induced phenomena. In this study, we make the As$\_$40/Ge$\_$10/Se$\_$15/S$\_$35//Ag thin film and then we measure the holographic diffraction efficiency according to thickness of Ag. And we form the two-dimensional holographic grating. At first, we formed one-dimensional grating and then we form two-dimensional grating by rotate the sample. We found out the most suitable thickness of Ag and in case of As$\_$40/Ge$\_$10/Se$\_$15/S$\_$35//Ag(600${\AA}$), the diffraction efficiency was more higher than other samples. The holographic grating was formed by He-Ne laser(λ=632.8nm). The intensity of incident beam was 2.5mW and incident angle was 20$^{\circ}$. We confirm. the two-dimensional holographic grating by the pattern of diffracted beam and AFM(Atomic Force Microscope) image. We perform the etching process using by 0.26N NaOH in order to confirm clearly two-dimensional grating.

• Applied Microscopy
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• v.47 no.1
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• pp.19-28
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• 2017

Since graphene was discovered in 2004, two-dimensional (2D) materials have been actively studied. Especially, 2D transition metal dichalcogenides (TMDs), such as $MoS_2$ and $WS_2$, have been the subject of significant research because of their exceptional optical, electrical, magnetic, catalytic, and morphological properties. Therefore, these materials are expected to be used in a variety of applications. Furthermore, tuning the properties of TMDs is essential to improve their performance and expand their applications. This review classifies the various doping methods of 2D TMDs, and it summarizes how the dopants interact with the materials and how the performance of the materials improves depending on the synthesis methods and the species of the dopants.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.631-635
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• 1996

Stress singularities appear at the interface edge in dissimilar materials also under thermal loading. First, these singularities then an interface meets a free side surface with an arbitrary angle are studied for a two-dimensional problem. The singular properties under thermal loading are made clear and the concrete singular field are obtained. Secondly, the dependence of stress field on elastic constants in axisymmetric dissimilar materials are. discussed. That is, it is shown that three elastic constants mutually independent are necessary, in general, to characterize the stress field of axisymmetric dissimilar materials, although Dunders' parameters defined for two-dimensional dissimilar materials have been often applied correspondingly also to axisymmetric problems.

• Applied Microscopy
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• v.45 no.3
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• pp.126-130
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• 2015

Raman spectroscopy is one of the most widely used tools in the field of graphene and two-dimensional (2D) materials. It is used not only to characterize structural properties such as the number of layers, defect densities, strain, etc., but also to probe the electronic band structure and other electrical properties. As the field of 2D materials expanded beyond graphene to include new classes of layered materials including transition metal dichalcogenides such as $MoS_2$, new physical phenomena such as anomalous resonance behaviors are observed. In this review, recent results from Raman spectroscopic studies on 2D materials are summarized.

• Fibers and Polymers
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• v.2 no.1
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• pp.163-172
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• 2001

To determine three-dimensional fiber orientation states in injection-molded short fiber composites a CLSM (Confocal Laser Scanning Microscope) is used. Since the CLSM optically sections the composites, more than two cross-sections either on or below the surface of the composite can be obtained. Three dimensional fiber orientation states can be determined with geometric parameters of fibers on two parallel cross-sections. For experiment, carbon fiber reinforced polystyrene is examined by the CLSM. Geometric parameters of fibers are measured by image analysis. In order to compactly describe fiber orientation states, orientation tensors are used. Orientation tensors are determined at different positions of the prepared specimen. Three dimensional orientation states are obtained without the difficulty in determining the out-of-plane angles by utilizing images on two parallel planes acquired by the CLSM. Orientation states are different at different positions and show the shell-core structure along the thickness of the specimen.

• Current Applied Physics
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• v.18 no.11
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• pp.1235-1239
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• 2018

We present a novel process to fabricate three-dimensional (3D) metallic patterns from 3D printed polymeric structures utilizing different hygroscopic swelling behavior of two different polymeric materials. 3D patterns are printed with two different polymers as cube shape. The surface of the 3D printed polymeric structures is plated with nickel by an electroless plating method. The nickel patterns on the surface of the 3D printed cube shape structure are formed by removing sacrificial layers using the difference in the rate of hygroscopic swelling between two printing polymer materials. The hygroscopic behavior on the interfaced structure was modeled with COMSOL Multiphysics. The surface and electrical properties of the fabricated three-dimensional patterns were analyzed and characterized.