• Carbon letters
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• v.13 no.1
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• pp.17-22
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• 2012

Currently, graphene is a topic of very active research in fields from science to potential applications. For various radio-frequency (RF) circuit applications including low-noise amplifiers, the unique ambipolar nature of graphene field-effect transistors can be utilized for high-performance frequency multipliers, mixers and high-speed radiometers. Potential integration of graphene on Silicon substrates with complementary metal-oxide-semiconductor compatibility would also benefit future RF systems. The future success of the RF circuit applications depends on vertical and lateral scaling of graphene metal-oxide-semiconductor field-effect transistors to minimize parasitics and improve gate modulation efficiency in the channel. In this paper, we highlight recent progress in graphene materials, devices, and circuits for RF applications. For passive RF applications, we show its transparent electromagnetic shielding in Ku-band and transparent antenna, where its success depends on quality of materials. We also attempt to discuss future applications and challenges of graphene.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.7-7
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• 2011

Graphene and graphene derivatives have attracted enormous attention from various research fields for applications in electronic devices, transparent electrodes, biosensors, drug delivery system and surface coatings. In the viewpoint of chemist, the chemical structure of graphene derivatives seems intriguing but detailed structures are being revealed only recently while engineering approaches for various applications are being executed very actively. In addition, cytotoxicity and mammalian cellular responses to graphene have not thoroughly investigated yet in spite of the importance in bio-applications and environment. In this talk, I'll introduce recent studies which report cytotoxicity and behaviors of mammalian cells when the cells are exposed to graphene (as well as some bio-applications of graphene), especially to get closer to answers to these questions, "how we understand and how/why we use graphene in biotechnology".

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.67-67
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• 2012

Graphene, two-dimensional one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, exhibits fascinating electrical properties, such as a linear energy dispersion relation and high mobility in addition to a wide-range optical absorption and high thermal conductivity. Graphene's outstanding tensile strength allows graphene-based electronic and photonic devices to be flexible, bendable, or even stretchable. Recently many groups have reported high performance electronic and optoelectronic devices based on graphene materials, i.e. field-effect transistors, gas sensors, nonvolatile memory devices, and plasmonic waveguides, in which versatile properties of graphene materials have been incorporated into a flexible electronic or optoelectronic platform. However, there are several fundamental or technological hurdles to be overcome in real applications of graphene in electronics and optoelectronics. In this tutorial we will present a short introduction to the basic material properties and recent progresses in applications of graphene to electronics and optoelectronics and discuss future outlook of graphene-based devices.

• Ceramist
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• v.22 no.3
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• pp.243-255
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• 2019

Graphene, a two-dimensional material with a single atomic layer, has recently become a major research focus in various applications such as electronic devices, sensors, energy storage, catalysts, and adsorbents, because of its large theoretical surface area, excellent electrical conductivity, outstanding chemical stability, and good mechanical properties. Recently, 3D nanoporous graphene structures have received tremendous attention to expand the application of 2D graphene. Here, we overview the synthesis of 3D nanoporous graphene network structure with two-dimensional graphite oxide sheets, the control of porous parameters such as specific surface area, pore volume and pore size etc, and the modification of electronic structure by heteroatom doping along with its various applications. The 3D nanoporous graphene shows superior performance in diverse applications as a promising key material. Consequently, 3D nanoporous graphene can lead the future for advanced nanotechnology.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.10-10
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• 2011

Graphene and graphene derivatives have attracted enormous attention from various research fields for applications in electronic devices, transparent electrodes, biosensors, drug delivery system and surface coatings. In the viewpoint of chemist, the chemical structure of graphene derivatives seems intriguing but detailed structures are being revealed only recently while engineering approaches for various applications are being executed very actively. Recently, several reports are available on interactions of graphene with biomolecules including proteins and nucleic acids. In this talk, I'll introduce recent studies which harness graphene derivatives for developing bioanalytical platforms to quantitatively analyze various enzyme activities. The systems rely on attractive interaction between graphene oxide and nucleic acids or phospholipids.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.6-6
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• 2011

Graphene, a monlayer of carbon atoms arrange to form a 2-dimensional honeycomb lattice, exhibits enormous fascinating properties, such as a linear energy dispersion relation, a wide-range optical absorption, high thermal conductivity, and mechanical flexibility [1]. Because the unique material properties of graphene allow it to be a promising building block for the next generation electronic and optoelectronic devices, sometimes graphene-based devices have refereed to be a strong candidate to overcome the intrinsic limitations of conventional semiconductor-based technology [2,3]. However, there are several fundamental or technological hurdles to be overcome in real applications of graphene in electronics and optoelectronics. In this tutorial we will present a short introduction to the basic materials properties and recent progress in applications of graphene and discuss future outlook of graphene-based electronic and optoelectronic devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.39-39
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• 2010

There have been many efforts to utilize the outstanding properties of graphene for macroscopic applications such as transparent conducting films useful for flexible/stretchable electronics. However, the lack of efficient synthesis, transfer, and doping methods limited the scale and the quality needed for the practical production of graphene films. In this presentation, we introduce ultra-large scale (~30 inch) synthesis and roll-to-roll transfer of graphene films showing excellent electrical and physical properties suitable for practical applications. Considering the outstanding scalability/processibility of roll-to-roll and CVD methods and the extraordinary flexibility/conductivity of graphene films, we expect the commercial production and application electrodes replacing the use of ITO can be realized in near future.

• Carbon letters
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• v.13 no.1
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• pp.1-16
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• 2012

The near explosion of attention given to graphene has attracted many to its research field. As new studies and findings about graphene synthesis, properties, electronic quality control, and possible applications simultaneous burgeon in the scientific community, it is quite hard to grasp the breadth of graphene history. At this stage, graphene's many fascinating qualities have been amply reported and its potential for various electronic applications are increasing, pulling in ever more newcomers to the field of graphene. Thus it has become important as a community to have an equal understanding of how this material was discovered, why it is stirring up the scientific community and what sort of progress has been made and for what purposes. Since the first discovery, the hype has expediently led to near accomplishment of industrial-sized production of graphene. This review covers the progress and development of synthesis and transfer techniques with an emphasis on the most recent technique of chemical vapor deposition, and explores the potential applications of graphene that are made possible with the improved synthesis and transfer.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.114-114
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• 2012

Even though graphene was introduced with a great hope to replace silicon in future, small (or zero) band gap and poor stability have become major challenges in graphene electronics. Especially, rectification and amplification function which are the elemental functions of silicon device, is very difficult to implement without a bandgap. However, the graphene can still be used in many other device applications if the merits of graphene are creatively utilized. For example, graphene can be applied to almost any kind of substrate. Its conductivity can be varied in some degree using electric field, charge dipole, attached molecules, and many other ways. Recently, graphene stacked with ferroelectric materials or piezoelectric materials has been actively studied for various device applications. In this talk, various device applications of graphene using hybrid stack or novel device structure will be introduced and their prospect will be discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.3-3
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• 2011

Graphene has been attracting much attention owing to its fascinating physical properties such as quantum electronic transport, a tunable band gap, extremely high mobility, elasticity, thermal conductivity, mechanical strength and so on. There have been many efforts to utilize these outstanding properties of graphene for macroscopic applications such as transparent conducting films useful for flexible/stretchable electronics. However, the scale and the quality graphene need to be further enhanced for practical applications by developing more efficient synthesis, transfer, and doping methods. In this tutorial, the recent advances in graphene synthesis and applications will be reviewed, and discuss the future directions of graphene research.