Sang Ouk Kim

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—A resistive switching memory device based on graphene oxide (GO) is presented. It is found that the resistive switching characteristic has a strong dependence on electrode material and GO thickness. In our experiment, an Al/GO/ITO structure with 30-nm-thick GO shows good switching performance with an on/off resistance ratio of 10 3 , low set/reset voltage,(More)
We present a flexible room temperature NO 2 gas sensor consisting of vertical carbon nanotubes ͑CNTs͒/reduced graphene hybrid film supported by a polyimide substrate. The reduced graphene film alone showed a negligible sensor response, exhibiting abnormal N–P transitions during the initial NO 2 injection. A hybrid film, formed by the growth of a vertically(More)
A sensitive open-type calorimeter was used to measure excess heat production during electrolysis in Li 2 SO 4 /H 2 O solution with Pt-anode and Pd-Ni thin film cathodes 9000 Å thick, sputtered on Al 2 O 3 substrate. In order to estimate the actual performance and possible measurement errors during electrolysis in the calorimeter used, including heat(More)
The refractive index of natural transparent materials is limited to 2-3 throughout the visible wavelength range. Wider controllability of the refractive index is desired for novel optical applications such as nanoimaging and integrated photonics. We report that metamaterials consisting of period and symmetry-tunable self-assembled nanopatterns can provide a(More)
Commercialization of graphene based applications inevitably requires cost effective mass production. From the early days of research on graphene, direct liquid phase exfoliation (LPE) of graphite has been considered as the most promising strategy to produce high-quality mono or few-layer graphene sheets in solvent dispersion forms. Substantial success has(More)
The ideal 1D structure of carbon nanotubes (CNTs) lends them various attractive properties such as tunable conductivity , extremely high electron mobility, and large charge storage capacity. [1,2] Owing to their molecular scale dimensions and unique electronic properties, CNTs are considered to be promising building blocks for future nanoelectronics(More)
Inverted Opals Offering well-defi ned pore size, high surface area, and pho-tonic bandgap tunability and having potential applications in membranes, [ 1 ] sensors, [ 2 ] superhydrophilic–phobic fi lms, [ 3 ] solar cells, [ 4 ] and photonic crystals, [ 5 ] 2D hexagonal structures and 3D inverted opal (IO) structures have recently been intensively studied. In(More)
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