• 한국재료학회지
• /
• 제28권8호
• /
• pp.466-473
• /
• 2018

Nickel oxide(NiO) thin films, nanorods, and carbon nanotube(CNT)/NiO core-shell nanorod structures are fabricated by sputtering Nickel at different deposition time on alumina substrates or single wall carbon nanotube templates followed by oxidation treatments at different temperatures, 400 and $700^{\circ}C$. Structural analyses are carried out by scanning electron microscopy and x-ray diffraction. NiO thinfilm, nanorod and CNT/NiO core-shell nanorod structurals of the gas sensor structures are tested for detection of $H_2S$ gas. The NiO structures exhibit the highest response at $200^{\circ}C$ and high selectivity to $H_2S$ among other gases of NO, $NH_3$, $H_2$, CO, etc. The nanorod structures have a higher sensing performance than the thin films and carbon nanotube/NiO core-shell structures. The gold catalyst deposited on NiO nanorods further improve the sensing performance, particularly the recovery kinetics.

• Korean Chemical Engineering Research
• /
• 제47권1호
• /
• pp.11-16
• /
• 2009

단일벽 탄소나노튜브의 표면 위에 동력학적 전위법으로 산화루테늄($RuO_2$)의 석출 및 루테늄-코발트 혼합산화물(Ru-Co mixed oxide)의 공석출에 의해 산화환원 수퍼커페시터용 복합전극을 제조하였다. 루테늄 성분이 13.13 wt%, 코발트 성분이 2.89 wt%가 석출된 Ru-Co 혼합산화물 전극은 낮은 전위 스캔속도($10\;mV\;s^{-1}$)에서는 $RuO_2$ 전극과 유사한 비용량(${\sim}620\;F\;g^{-1}$)을 나타내지만, 높은 스캔속도($500\;mV\;s^{-1}$)에서는 $RuO_2$ 전극보다 큰 비용량을 보인다. 높은 스캔 속도에서 Ru-Co 혼합산화물 전극이 비용량의 증가를 나타내는 것은 Ru 성분을 통한 전기전도성을 Co 성분이 구조적으로 지지해주기 때문이다.

• 폴리머
• /
• 제34권3호
• /
• pp.198-201
• /
• 2010

탄소나노튜브의 응집력을 완화하기 위한 표면 개질과 고분자 소재와의 상용성을 유도하기 위하여, 친수성 고분자를 도입하는 연구를 진행하였다. 산처리를 통한 표면 기능화를 시행하였으며, 카복실기 도입 탄소나노튜브를 thionyl chloride을 사용하여 acyl chloride로 치환한 후 저분자량의 아민 말단 poly(ethylene oxide)를 공유결합으로 도입하였다. TGA를 통하여 탄소나노튜브 표면에 도입된 고분자의 함량을 계산하였으며, 탄소나노튜브 표면에 도입된 고분자의 표면 형상을 SEM과 TEM을 통하여 직경이 증가하는 것을 확인할 수 있었다.

• Carbon letters
• /
• 제13권3호
• /
• pp.157-160
• /
• 2012

In this work, iron oxide ($Fe_3O_4$) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by a simple chemical coprecipitation method and $Fe_3O_4$-decorated MWNTs (Fe-MWNTs)/polypyrrole (PPy) nanocomposites (Fe-MWNTs/PPy) were prepared by oxidation polymerization. The effect of the PPy on the electrochemical properties of the Fe-MWNTs was investigated. The structures characteristics and surface properties of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were characterized by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical performances of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were determined by cyclic voltammetry and galvanostatic charge/discharge characteristics in a 1.0 M sodium sulfite electrolyte. The results showed that the Fe-MWNTs/PPy electrode had typical pseudo-capacitive behavior and a specific capacitance significantly greater than that of the Fe-MWNT electrode, indicating an enhanced electrochemical performance of the Fe-MWNTs/PPy due to their high electrical properties.

• 한국재료학회지
• /
• 제18권10호
• /
• pp.529-534
• /
• 2008

The hydrogen gas sensing properties of a zinc oxide nanowire structure were studied. Porous zinc oxide nanowire structures were fabricated by oxidizing zinc deposited on a single-wall carbon nanotube (SWNT) template. This revealed a porous ZnO-SWNT composite due to the porosity in the SWNT film. The gas sensing properties were compared with those of zinc oxide thin films deposited on SiO2/Si substrates in sensitivity and operating temperature. The composite structure showed higher sensitivity and lower operating temperature than the zinc oxide film. It showed a response even at room temperature while the film structure did not.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.119-119
• /
• 2016

Over the last years the anodic formation of ordered $TiO_2$ nanotube layers has created significant scientific interest. Titanium oxide nanotube formation on the titanium or titanium alloy surface is expected to be important to improve cell adhesion and proliferation under clinical conditions. It should be possible to control the nanotube size and morphology for biomedical implant use by controlling the applied voltage, alloying element, current density, anodization time, and electrolyte. $TiO_2$ nanotubes show excellent biocompatibility, and the open volume in the tubes may be exploited as a drug release platform and so on. Therefore, in this study, Nanotube shape on the Ti-29Nb-xHf alloys with applied potentials was reserched. $TiO_2$ nanotube formation on Ti-29Nb-xHf alloys was carried out using anodization technique as a function of applied DC potential (10 V to 30 V and 30 V to 10 V) and anodization time for 60~120 min in $1MH_3PO_4$ with small additions of (0.8 wt. %, to 1.2 wt. %) NaF. The morphology change of anodized Ti-29Nb-xHf alloys was determined by FE-SEM, XRD, and EDS.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.681-682
• /
• 2011

• Transactions on Electrical and Electronic Materials
• /
• 제12권2호
• /
• pp.43-50
• /
• 2011

Carbon-nanotube metal oxide semiconductor field effect transistor (CN-MOSFET) is a promising future device candidate. The electrical characteristics of 16 nm N-type CN-MOSFETs are explored in this paper. The optimum N-type CN-MOSFET device profiles with different number of tubes are identified for achieving the highest on-state to off-state current ratio ($I_{on}/I_{off}$). The influence of substrate voltage on device performance is also investigated in this paper. Tradeoffs between subthreshold leakage current and overall switch quality are evaluated with different substrate bias voltages. Technology development guidelines for achieving high-speed, low-leakage, area efficient, and manufacturable carbon nanotube integrated circuits are provided.

• 한국세라믹학회지
• /
• 제54권1호
• /
• pp.66-69
• /
• 2017

In this study, the fabrication and electrical properties of aligned single-walled carbon nanotube (SWCNT) networks using a template-based fluidic assembly process are presented. This complementary metal-oxide-semiconductor (CMOS)-friendly process allows the formation of highly aligned lateral nanotube networks on $SiO_2/Si$ substrates, which can be easily integrated onto existing Si-based structures. To measure outstanding electrical properties of organized SWCNT devices, interfacial contact resistance between organized SWCNT devices and Ti/Au electrodes needs to be improved since conventional lithographic cleaning procedures are insufficient for the complete removal of lithographic residues in SWCNT network devices. Using optimized purification steps and controlled developing time, the interfacial contact resistance between SWCNTs and contact electrodes of Ti/Au is reached below 2% of the overall resistance in two-probe SWCNT platform. This structure can withstand current densities ${\sim}10^7A{\cdot}cm^{-2}$, equivalent to copper at similar dimensions. Also failure current density improves with decreasing network width.

• Journal of Magnetics
• /
• 제16권4호
• /
• pp.413-416
• /
• 2011

An array of FeCo nanotubes has been successfully fabricated in the pores of porous anodic aluminum oxide (AAO) templates by wetting templates method. The morphology and structure of the nanotube array were characterized by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The average diameter of the nanotubes was about 200 nm, and the length was more than 10 ${\mu}m$. Vibrating sample magnetometer and superconducting quantum interference device were used to investigate the magnetic properties of the nanotube array. Interaction between the nanotubes has been found to be demagnetizing as expected and the switching field distribution is broad.