Samsung

About: Samsung is a company organization based out in Seoul, South Korea. It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 134067 authors who have published 163691 publications receiving 2057505 citations. The organization is also known as: Samsung Group & Samsung chaebol.

Restacking-Inhibited 3D Reduced Graphene Oxide for High Performance Supercapacitor Electrodes

Abstract: Graphene has received considerable attention in both scientific and technological areas due to its extraordinary material properties originating from the atomically single- or small number-layered structure. Nevertheless, in most scalable solution-based syntheses, graphene suffers from severe restacking between individual sheets and thus loses its material identity and advantages. In the present study, we have noticed the intercalated water molecules in the dried graphene oxide (GO) as a critical mediator to such restacking and thus eliminated the hydrogen bonding involving the intercalated water by treating GO with melamine resin (MR) monomers. Upon addition of MR monomers, porous restacking-inhibited GO sheets precipitated, leading to the carbonaceous composite with an exceptionally large surface area of 1040 m2/g after a thermal treatment. Utilizing such high surface area, the final graphene composite exhibited excellent electrochemical performance as a supercapacitor electrode material: specific capac...

A 20nm 1.8V 8Gb PRAM with 40MB/s program bandwidth

Abstract: Phase-change random access memory (PRAM) is considered as one of the most promising candidates for future memories because of its good scalability and cost-effectiveness [1]. Besides implementations with standard interfaces like NOR flash or LPDDR2-NVM, application-oriented approaches using PRAM as main-memory or storage-class memory have been researched [2–3]. These studies suggest that noticeable merits can be achieved by using PRAM in improving power consumption, system cost, etc. However, relatively low chip density and insufficient write bandwidth of PRAMs are obstacles to better system performance. In this paper, we present an 8Gb PRAM with 40MB/s write bandwidth featuring 8Mb sub-array core architecture with 20nm diode-switched PRAM cells [4]. When an external high voltage is applied, the write bandwidth can be extended as high as 133MB/s.

Probing graphene grain boundaries with optical microscopy

Abstract: Grain boundaries in graphene are formed by the joining of islands during the initial growth stage, and these boundaries govern transport properties and related device performance. Although information on the atomic rearrangement at graphene grain boundaries can be obtained using transmission electron microscopy and scanning tunnelling microscopy, large-scale information regarding the distribution of graphene grain boundaries is not easily accessible. Here we use optical microscopy to observe the grain boundaries of large-area graphene (grown on copper foil) directly, without transfer of the graphene. This imaging technique was realized by selectively oxidizing the underlying copper foil through graphene grain boundaries functionalized with O and OH radicals generated by ultraviolet irradiation under moisture-rich ambient conditions: selective diffusion of oxygen radicals through OH-functionalized defect sites was demonstrated by density functional calculations. The sheet resistance of large-area graphene decreased as the graphene grain sizes increased, but no strong correlation with the grain size of the copper was revealed, in contrast to a previous report. Furthermore, the influence of graphene grain boundaries on crack propagation (initialized by bending) and termination was clearly visualized using our technique. Our approach can be used as a simple protocol for evaluating the grain boundaries of other two-dimensional layered structures, such as boron nitride and exfoliated clays.

Novel BOD (biological oxygen demand) sensor using mediator-less microbial fuel cell

Abstract: A microbial fuel cell type of biosensor was used to determine the biochemical oxygen demand (BOD) of wastewater. The biosensor gave a good correlation between the BOD value and the coulomb produced. The BOD sensor has been operated for over 5 years in a stable manner without any servicing. This is much longer that that of previously reported BOD biosensors.