• Journal of Electrochemical Science and Technology
• /
• v.7 no.1
• /
• pp.82-89
• /
• 2016

In this work, a ruthenium dioxide electrode has been prepared by thermal decomposition at 400 ℃ then used for the oxidation of commercial amoxicillin. The physical characterization showed that RuO₂ electrode presents a mud cracked structure. Its electrochemical characterization has revealed an increase of the voltammetric charge in acid electrolyte compared to neutral electrolyte indicating the importance of protons in its surface redox processes. The voltammetric study of the oxidation of amoxicillin has been investigated. It has been obtained that the oxidation of amoxicillin is controlled by both adsorption and diffusion processes. Moreover, the oxidation of amoxicillin occurs via direct and indirect processes in free or electrolyte containing chlorides. Through preparative electrolysis, enhancement of amoxicillin oxidation was observed in the presence of chloride where the amoxicillin degradation yield reached more than 50 % compared to less than 5% in the absence of chlorides. Spectrophotometric investigations have revealed the degradation of intermediates absorbing at 350 nm.

• KSBB Journal
• /
• v.32 no.1
• /
• pp.35-45
• /
• 2017

In this work the optical fiber glucose and lactate biosensors were developed by using fluorescent dye and enzyme immobilized on the end tip of an optical fiber. 3-Glycidyloxypropyl)methyldiethoxysilane (GPTMS), (3-Aminopropyl) trimethoxysilane (APTMS) and Methyltrimethoxysilane (MTMS) were used to immobilize glucose oxidase (GOD), lactate oxidase (LOD) and ruthenium(II) complex (tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II), $Ru(dpp)_3^{2+}$) as oxygen sensitive fluorescent dye. MTMS sol-gel was an excellent supporting material for the immobilization of $Ru(dpp)_3^{2+}$, GOD, and LOD on the optical fiber. Storage stability of the optical fiber glucose sensor was kept constant over 20 days, while the optical fiber lactate sensor had constant storage stability over 17 days. The optical fiber glucose and lactate biosensors also maintained good operational stability for 20 hours and 14 hours, respectively. The activities of the immobilized enzymes were most excellent at pH 7 and at $25^{\circ}C$. On-line monitoring of glucose and lactate in a simulated process was performed with the optical fiber glucose and lactate biosensors. On-line monitoring results were agreed with those of off-line data measured with high performance liquid chromatography (HPLC).

• Journal of Magnetics
• /
• v.10 no.2
• /
• pp.48-51
• /
• 2005

The spin transfer induced magnetization switching has been reported to occur in magnetic multilayer structures whose scope usually consists of one stack of ferromagnetic / non-ferromagnetic / ferromagnetic (F / N / F) materials. In this work, it is shown that: 1) Copper used as a buffer layer between the free Co and the Au cap-layer can clearly increase the probability to get the spin transfer induced magnetization switching in a simple spin valve Co 11 / Cu 6/ Co 2 (nm); 2) Furthermore, when Ruthenium is simultaneously applied as a buffer layer on the Si-substrate, the critical switching currents can be reduced by $30\%$, and the absolute resistance change delta R $[{\Delta}R]$ of that stack can be enlarged by $35\%$. The enhancement of the spin transfer induced magnetization switching can be ascribed to a lower local stress in the thin Co layer caused by a better lattice match between Co and Cu and the smoothening effect of Ru on the thick Co layer.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.6
• /
• pp.460-465
• /
• 1994

New silicon-monosubstituted (${\eta}^4$-2,3,4,5-tetraphenyl-l-silacyclopentadiene)transi tion metal complexes are described. (7-Alkyl-7-silanorbornadienyl)MLn(Alkyl=Methyl: MLn=CpRu$(CO)_2$: Alkyl=Methyl: MLn=CpNi(CO): Alkyl=Ethyl: MLn=CpNi(CO)) complexes were prepared from the corresponding silole-transition metal complexes with dimethylacetylenedicarboxylate. Cycloaddition products were obtained with 2,3-dimethyl-1,3-butadiene, 2,3-butanedione, and 1,4-benzoquinone through the ruthenium-substituted silylene. We have determined the crystal structure of (1-methyl-2,3,4,5-tetraphenyl-l-silacyclopentadien yl)cyclopentadienyldicarbonylruthenium by using graphite monochromated Mo-Ka radiation. The compound was crystallized in the monoclinic space group $P2_{1/c}$ with a = 9.838(l), b = 15.972(3), c = 18.327(3) ${\AA}$, and ${\beta}= 94.28(l)^{circ}$. The ruthenium moiety CpRu$(CO)_2$ on silicon is in an axial position.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.57-57
• /
• 2009

반도체 device가 고집적화 및 다층화 되어짐에 따라 현재 사용되고 있는 구리 interconnect의 확산방지막인 Ta/TaN은 많은 문제가 발생하고 있다. 고집적화 된 반도체 소자에 적용시키기에는 Ta/TaN 확산 방지막의 고유 저항값이 매우 크고, 구리의 증착에 필요한 seed layer의 크기도 문제화 된다고 보고되어지고 있다. 이러한 이유로 인해 점차 고집적화 되어지는 반도체 기술에 맞추어 새로운 확산 방지막에 대한 연구가 현재 활발히 이루어지고 있다. 이에 새로운 확산 방지막으로써 대두되고 연구되고 있는 재료가 Ruthenium (Ru)이다. Ru은 공기 중에서 매우 안정하고 고유저항 값 또한 $13\;{\mu}{\Omega}\;cm$의 Ta에 비해 $7.1\;{\mu}{\Omega}\;cm$의 매우 작은 고유저항 특성을 가지고 있다. 또한, Ru은 구리와의 우수한 접착성으로 인해 구리의 interconnect의 형성에 있어 seed layer가 필요하지 않을 뿐만 아니라 높은 annealing 온도에서도 무시할 만큼 작은 solid solubility를 가지며 구리와의 계면에서 새로운 화합물을 형성하지 않으며 annealing시 구리의 delamination을 유발시키지도 않는다. 이에 따라, 평탄화와 소자 분리를 위하여 chemical mechanical planarization (CMP) 공정이 필요하게 되었다. 하지만, Ru의 noble한 성질과 Ru 확산방지막 CMP공정 시 노출되는 다른 이종 물질 사이의 최적화 된 selectivity를 구현하는데 많은 어려움이 있다. 이로인해 Ru 확산 방지막을 위한 CMP slurry에 대한 연구는 아직 미흡한 수준이다. 본 연구에서는 Ru이 확산방지막으로 사용되었을 때 이를 위한 CMP slurry에 대한 평가와 연구가 이루어졌다. Slurry 조성과 농도 및 pH에 따른 전기 화학적 분석을 통하여 slurry 내에서 각각의 막질들이 어떠한 상태로 존재하는지 분석해 보았다. 또한, Ru을 비롯한 이종막질들의 etch rate, removal rate와 selectivity에 대한 연구가 진행되었다. 최종적으로 Ru 확산방지막 CMP를 위한 최적화된 slurry를 제안하였다.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.10
• /
• pp.1525-1528
• /
• 2005

The synthesis and characterization of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O\;(C_2O_4}^{2-}$ = oxalato anoin) complex are described, and its redox properties (in buffer solution of pH = 12) have been investigated. This complex is used for in situ generation of oxoruthenates complexes which have been characterized by electronic spectroscopy. Reaction of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${S_2O_8}^{2-}$ in molar KOH generates trans-${[RuO_3(OH)_2]^{2-}/S_2O_8}^{2-}$ reagent while with excess ${BrO_3}^-$ in molar $Na_2CO_3$ generates ${[RuO_4]^-/BrO_3}^-$ reagent. Avoiding the direct use of [$RuO_4$] the organic-soluble $(n-Pr_4N)^+[RuO_4]^-$, (TPAP) has been isolated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${BrO_3}^-$ in molar carbonate and n-$Pr_4$NOH. In a mixture of $H_2O/CCl_4$ ruthenium tetraoxide can be generated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${IO_4}^-$. The catalytic activities of oxoruthenates that have been made from $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ towards the oxidation of benzyl alcohol, piperonyl alcohol, benzaldehyde and benzyl amine at room temperature have been studied.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.152-152
• /
• 1999

1Gb급 이상 기억소자의 캐패시터 재료로 주목받고 있는 (Ba,Sr)TiO3 [BST] 박막의 전극재료로는 Pt, Ru, Ir과 같은 금속전극과 RuO2, IrO2와 산화물 전도체가 유망한 것으로 알려져 있다. 그런데, DRAM의 집적도가 증가하게 되면, BST같은 고유전율 박막을 유전재료로 사용한다 하더라도, 3차원적인 구조가 불가피하게 때문에 기존의 sputtering 방법으로는 우수한 단차피복성을 얻기 힘들므로, MOCVD법이 필수적이다. 본 연구에서는 기존에 연구되었던 Pt에 비해 식각특성이 우수하고, 비교적 낮은 비저항을 갖는 Ru 박막증착에 대한 연구를 행하였다. 본 연구에서는 수직형의 반응기와 저항 가열 방식의 susceptor로 구성된 저압 유기금속 화학증착기를 사용하여 최대 6inch 직경을 갖는 기판 위에 Ru박막을 증착하였다. Precursor로는 기존에 연구된 적이 없는 bis-(ethyo-$\pi$-cyclopentadienyl)Ru (Ru(C5H4C2H5)2, [Ru(EtCp)2])를 사용하였으며, bubbler의 온도는 85$^{\circ}C$로 하였다. Si, SiO2/Si를 사용하였으며, 증착온도 25$0^{\circ}C$~40$0^{\circ}C$, 증착압력 3Torr의 조건에서 Ru 박막을 증착하였다. Presursor를 운반하는 수송기체로는 Ar을 사용하였으며, carbon과 같은 불순물의 제거를 위해 O2를 첨가하였다. 증착된 박막은 XRD, SEM, 4-point probe등을 통해 구조적, 전기적 특성을 평가하였으며, 열역학 계산을 위해서는 SOLGASMIX-PV프로그램을 사용하였다. Ru 박막의 증착에 있어서 산소의 첨가는 필수적이었으며, Ru 박막의 증착속도는 30$0^{\circ}C$~40$0^{\circ}C$의 온도 영역에서 200$\AA$/min으로 일정하였으며, 첨가된 산소의 양이 적을수록 더 치밀하고 평탄한 표면형상을 보였으며, 또한 더 낮은 전기 전도도를 보였다. 그리고 증착된 박막은 12~15$\mu$$\Omega$cm 정도의 낮은 비저항 값을 나타냈으며 이것은 기존의 sputtering 법에 의해 증착된 Ru 박막의 비저항 값들과 비교될만하다. 한편, 높은 온도, 높은 산소분압 조건에서 RuO2의 형성을 관찰하였으며, 이것은 열역학적인 계산을 통해서 잘 설명할 수 있었다.

• Korean Journal of Metals and Materials
• /
• v.50 no.3
• /
• pp.243-247
• /
• 2012

A ruthenium (Ru) catalytic layer and a conventional Pt layer were assessed as counter electrodes (CE) for dye sensitized solar cells (DSSCs). Ru films with different thicknesses of 34, 46, and 90 nm were deposited by atomic layer deposition (ALD). Pt layers with the same thicknesses were prepared by sputtering. $0.45cm^2$ DSSCs were prepared and their properties were characterized by FE-SEM, cyclic voltammetry (CV), impedance spectroscopy (EIS), and current-voltage (I-V). FE-SEM revealed that the crystallized Ru films and Pt films had been deposited quite conformally. CV showed that the catalytic activity of Pt was much greater than that of Ru. In addition, although the catalytic activity of Pt did not depend on the thickness, that of Ru showed an increase with increasing thickness. Impedance analysis revealed high charge transfer resistance at the Ru interface and a decrease with increasing Ru thickness, whereas Pt showed low resistance with no thickness dependence. Despite the relatively small catalytic activity of Ru, the I-V result revealed the average energy conversion efficiency of Ru and Pt to be 2.98% and 6.57%, respectively. These results suggest that Ru can be used as counter electrodes in DSSCs due to its extremely low temperature process compatibility.

• Applied Chemistry for Engineering
• /
• v.33 no.1
• /
• pp.103-108
• /
• 2022

This research work reports the development of a Ruthenium/2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO)/nitrate catalyst system for the highly selective transformation of isosorbide (1,4:3,6-dianhydro-D-glucitol) to isosorbide-diketone (2,6-dioxabicyclo (3,3,0)octan-4,8-one). Isosorbide is a critical platform molecule for future manufacturing processes. TEMPO has been utilized to convert alcohols to carbonyl compounds for a long time. The optimal chemical reaction condition was found to be when using isosorbide (0.5 mmol) with supported Ru (10 mol%), TEMPO (5 mol%), and sodium nitrate (0.03 mmol) in the presence of acetic acid (3 ml) as a solvent at 50 ℃ and 1 atm oxygen pressure. This catalyst system demonstrated good selectivity (> 97%) and yield (87%) with respect to the desired product, in addition to a putative catalytic double oxidation mechanism.

• Journal of the Korean Chemical Society
• /
• v.49 no.1
• /
• pp.78-82
• /
• 2005