Sung Myung

Nanotube Electronics: A flexible approach to mobility

An innovative and scalable strategy for making high-density arrays of aligned nanotubes could lead to the mass-production of high-performance, high-power flexible electronics.

GRAPHENE-ENCAPSULATED NANOPARTICLE-BASED BIOSENSOR FOR THE SELECTIVE DETECTION OF BIOMARKERS

Nanomaterials such as silicon nanowires (SiNWs), [ 1 , 2 ] carbon nanotubes (CNTs), [ 3–6 ] and graphene, [ 7,8 ] have gained much attention for use in electrical biosensors due to their nanoscopic and electrical properties. For instance, SiNWs and CNTs can be integrated into fi eld-effect transistors (FETs) to detect small amounts of target biomolecules with high sensitivity and selectivity by measuring electrical disturbances induced by the binding of these biomolecules to the surface of the nanostructure. [ 9,10 ] The detection of biomarker proteins with high sensitivity and selectivity is vital for the early diagnosis of many diseases including cancer and HIV. For this purpose, carbonbased nanomaterials such as CNTs and graphene have attracted signifi cant attention for fabricating highly sensitive FET-based biosensors. [ 6 , 8,9 , 11–15 ] In particular, the use of graphene in FETbased biosensors is becoming more and more appealing not only due to its unique properties, such as higher 2D electrical conductivity, superb mechanical fl exibility, large surface area, and high chemical and thermal stability, but also due to its ability to overcome the limitations of CNTs, such as variations in electrical properties of CNT-based devices and the limited surface area of CNTs. [ 16–24 ] Nevertheless, there have been only a few reports on the development of graphene FET-based biosensors, [ 14 , 25 ] and their potential as biosensors has not been fully explored. It is therefore critical to develop nanoscopic graphenebased biosensors that are simple in device structure, small in size, and allow label-free detection and real-time monitoring of biomarkers, all of which are essential criteria for biosensors. A key challenge in the above requirements is the achievement of both, well-organized 2D or 3D graphene structures, in microscopic and nanoscopic biosensing devices and well-defi ned bioconjugation chemistry on graphene.

Linker-free directed assembly of high-performance integrated devices based on nanotubes and nanowires

Advanced electronic devices based on carbon nanotubes (NTs) and various types of nanowires (NWs) could have a role in next-generation semiconductor architectures. However, the lack of a general fabrication method has held back the development of these devices for practical applications. Here we report an assembly strategy for devices based on NTs and NWs. Inert surface molecular patterns were used to direct the adsorption and alignment of NTs and NWs on bare surfaces to form device structures without the use of linker molecules. Substrate bias further enhanced the amount of NT and NW adsorption. Significantly, as all the processing steps can be performed with conventional microfabrication facilities, our method is readily accessible to the present semiconductor industry. We use this method to demonstrate large-scale assembly of NT- and NW-based integrated devices and their applications. We also provide extensive analysis regarding the reliability of the method.

Limits on WIMP-nucleon cross section with CsI(Tl) crystal detectors

The Korea Invisible Mass Search(KIMS) experiment presents new limits on WIMP-nucleon cross section using the data from an exposure of 3409 kgd taken with low background CsI(Tl) crystals at Yangyang underground laboratory. The most stringent limit on the spin dependent interaction for pure proton case is obtained. The DAMA signal region for both spin independent and spin dependent interactions for the WIMP mass higher than 20 GeV/c^2are excluded by the single experiment with crystal scintillators.

Ambipolar Memory Devices Based on Reduced Graphene Oxide and Nanoparticles

[*] Prof. S. Hong, S. Myung, H. Lee Department of Physics and Astronomy, Seoul National University Seoul 151-747 (Korea) Department of Biophysics and Chemical Biology, Seoul National University Seoul 151-747 (Korea) E-mail: shong@phya.snu.ac.kr Prof. K. S. Kim, J. Park Center for Superfunctional Materials, Department of Chemistry Pohang University of Science and Technology Pohang 790-784 (Korea) E-mail: kim@postech.ac.kr

New Limits on Interactions between Weakly Interacting Massive Particles and Nucleons Obtained with CsI(Tl) Crystal Detectors

The Korea Invisible Mass Search (KIMS) experiment presents new limits on the weakly interacting massive particle (WIMP)-nucleon cross section using data from an exposure of 3409 kg.d taken with low-background CsI(Tl) crystals at the Yangyang Underground Laboratory. The most stringent limit on the spin-dependent interaction for a pure proton case is obtained. The DAMA signal region for both spin-independent and spin-dependent interactions for the WIMP masses greater than 20 GeV/c2 is excluded by the single experiment with crystal scintillators.

Carbon Nanotube and Graphene Hybrid Thin Film for Transparent Electrodes and Field Effect Transistors

S. H. Kim, [+] Dr. W. Song, [+] M. W. Jung, M.-A. Kang, K. Kim, Dr. S. S. Lee, Dr. J. Lim, Dr. S. Myung, Dr. K.-S. An Thin Film Materials Research Group Korea Research Institute of Chemical Technology (KRICT) Yuseong Post Offi ce Box 107 Daejeon 305-600 , Republic of Korea E-mail: msung@krict.re.kr Dr. S.-J. Chang Department of Chemistry Chung-Ang University 84 Heukseok-ro , Dongjak-gu, Seoul 156-756 , Korea Prof. J. Hwang Department of Materials Science and Engineering Hongik University Seoul 121-791 , Republic of Korea

Wafer-Scale, Homogeneous MoS2 Layers on Plastic Substrates for Flexible Visible-Light Photodetectors

An appropriate solution is suggested for synthesizing wafer-scale, continuous, and stoichiometric MoS2 layers with spatial homogeneity at the low temperature of 450 °C. It is also demonstrated that the MoS2 -based visible-light photodetector arrays are both fabricated on 4 inch SiO2 /Si wafer and polyimide films, revealing 100% active devices with a narrow photocurrent distribution and excellent mechanical durability.

CaMoO/sub 4/ scintillation crystal for the search of /sup 100/Mo double beta decay

Scintillation properties of calcium molybdate are investigated. The emission spectrum is broad with a maximum at 520 nm. At room temperature the light yield is 4% of CsI(Tl) (400 photoelectrons/MeV) and the decay time is 17 /spl mu/s. During cooling the light yield and decay time increase. Prospects of optimization of this scintillator are also discussed. The feasibility of the material for the search of neutrinoless double beta decay of /sup 100/Mo is analyzed. A half life limit of T/sub 1/2/=1/spl middot/10/sup 25/ years (68% CL) seems feasible with CaMoO/sub 4/ scintillator, running with 10 kg of /sup 100/Mo for 5 years. The background due to two neutrino double beta decay of /sup 48/Ca is also considered. Requirements for new scintillators for double beta decay search are formulated.

Label-free polypeptide-based enzyme detection using a graphene-nanoparticle hybrid sensor.

A graphene-nanoparticle (NP) hybrid biosensor that utilizes an electrical hysteresis change to detect the enzymatic activity and concentration of Carboxypeptidase B was developed. The results indicate that the novel graphene-NP hybrid biosensor, utilizing electrical hysteresis, has the ability to detect concentrations of targeted enzyme on the micromolar scale. Furthermore, to the knowledge of the authors, this is the first demonstration of a graphene-based biosensor that utilizes a hysteresis change resulting from metallic NPs assembled on a graphene surface.