• 한국전기전자재료학회논문지
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• 제28권3호
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• pp.154-159
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• 2015

In this paper, we propose a numerical method to model temperature dependent threshold voltage shift observed in metal oxide thin-film transistors (TFTs). The proposed model is then implemented in AIM-SPICE circuit simulation tool. The proposed method consists of modeling the well-known stretched-exponential time dependent threshold voltage shift and their temperature dependent coefficients. The outputs from AIM-SPICE tool and the stretched-exponential model at different temperatures in the literature are compared and they show a good agreement. Since metal oxide TFTs are the promising candidate for flat panel displays, the proposed method will be a good stepping stone to help enhance reliability of fast-evolving display circuits.

• 센서학회지
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• 제25권2호
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• pp.103-109
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• 2016

Recent light-enhanced metal oxide gas sensors are reviewed in this article. The basic mechanisms of a light-enhanced metal oxide gas sensor are discussed. Many literatures reveal that the standalone sensitivity and the response/recovery time enhancements enabled by the exposing light are not as high as the performance enhancement provided by external heating. Therefore, both optimal amount of external heating and exposed light intensity are necessary to increase the performance of these light-enhanced gas sensors. The development of highly light sensitive materials and structures is important to lower the overall power consumptions of the sensors.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.432-434
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• 2009

Metal nano-wire arrays on Cu-coated seed layers were fabricated by aqueous solution method using sulfate bath at room temperature. The seed layers were coated on Anodic aluminum oxide (AAO) bottom substrates by electrochemical deposition technique, length and diameter of metal nano-wires were dominated by controlling the deposition parameters, such as deposition potential and time, electrolyte temperature. Anodic aluminum oxide (AAO) was used as a template to prepare highly ordered Ni, Fe, Co and Cu multilayer magnetic nano-wire arrays. This template was fabricated with two-step anodizing method, using dissimilar solutions for Al anodizing. The pore of anodic aluminum oxide templates were perfectly hexagonal arranged pore domains. The ordered Ni, Fe, Co and Cu systems nano-wire arrays were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Vibrating Sample Magnetometer (VSM). The ordered Ni, Fe, Co and Cu systems nano-wires had different preferred orientation. In addition, these nano-wires showed different magnetization properties under the electrodepositing conditions.

• 한국세라믹학회지
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• 제55권1호
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• pp.1-20
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• 2018

Semiconducting nanomaterials have attracted considerable interest in recent years due to their high sensitivity, selectivity, and fast response time. In addition, for portable applications, they have low power consumption, lightweight, simple in operation, a low maintenance cost. Furthermore, it is easy to manufacture microelectronic sensor structures with metallic oxide sensitive thin layers. The use of semiconducting metal oxides to develop highly sensitive chemiresistive sensing systems remains an important scientific challenge in the field of gas sensing. According to the sensing mechanisms of gas sensors, the overall sensor conductance is determined by surface reactions and the charge transfer processes between the adsorbed species and the sensing material. The primary goal of the present study is to explore the possibility of using semiconducting mixed metal oxide nanostructure as a potential sensor material for selective gases.

• 센서학회지
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• 제29권6호
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• pp.369-373
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• 2020

A hydrogen sensor was fabricated by utilizing a bundle of metal oxide nanostructures whose growth positions were selectively controlled by utilizing graphene, which is a carbon of atomic-unit thickness. To verify the reducing ability of graphene, it was confirmed that the multi-composition metal oxide V₂O₅ was converted into VO₂ on the graphene surface. Because of the role of graphene as a reducing catalyst, it was confirmed that ZnO and MoO₃ nanostructures were grown at high density only on the graphene surface. The fabricated gas sensor showed excellent sensitivity.

• Environmental Engineering Research
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• 제10권2호
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• pp.45-53
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• 2005

Metal oxide particles with mole ratio of aluminum: titanium of 1:1 were synthesized by a sol-gel method. Langmuir (a) and Freundlich (b) adsorption isotherms of dissolved lead [Pb(Ⅱ)] ion on the metal oxide particles containing aluminum and titanium were determined as follows, respectively,(a) , (b) at pH 6where, correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.95 and 0.96, respectively.The overall adsorption rate of Pb(Ⅱ) on the metal oxide particles containing aluminum and titanium was determined by a differential bed reactor. The overall adsorption rate at pH 6 was as a following equation.at pH 6

• Current Photovoltaic Research
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• 제11권1호
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• pp.13-17
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• 2023

Functional transparent electrode was achieved by metal oxide-metal-Metal oxide (OMO) structure. Tailoring of metal oxide and metal layers, optically transparent and electrically excellent OMO films were investigated. Silver (Ag) is adopted for the metal layer and Ag oxide (AgO) is reactively formed by flowing O₂ gas during the sputtering process. This spontaneous AgO formation from Ag simultaneously provides the good electrical interface with high transparency. Due to the feature of transparent electrode of OMO, it endows the shielding effect (SE) function of electromagnetic interference. Optically transparent and electrically conductive OMO electrode shows the high transmittance (83.7%) and low sheet resistance (6.5 Ω/☐) with SE of 29.54 dB.

• Journal of Electrochemical Science and Technology
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• 제3권1호
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• pp.35-43
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• 2012

Highly ordered and perforated anodic aluminum oxide membranes were prepared by anodic oxidation and subsequent removal of the barrier layer. By using these homemade anodic aluminum oxide membranes as templates, metal selenide nanowires and nanotubes were synthesized. The structure and composition of these one-dimensional nanomaterials were studied by field emission scanning electron microscopy as well as transmission electron microscopy and energy dispersive X-ray spectroscopy. The growth process of metal selenide inside anodic aluminum oxide channel was traced by investigating the series of samples using scanning electron microscopy after reacting for different times. Straight and dense copper selenide and silver selenide nanowires with a uniform diameter were successfully prepared. In case of nickel selenide, nanotubes were preferentially formed. Phase and crystallinity of the nanostructured materials were also investigated.

• 전자공학회논문지D
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• 제36D권3호
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• pp.34-40
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• 1999

최근, 플라즈마 공정에 의해 발생하는 게이트 산화막의 손상은 게이트 산화막의 두께가 10nm이하로 감소함에 따라서 가정 중요한 신뢰성 문제들 중의 하나가 되고 있다. 플라즈마로 인한 손상은 metal 안테나 테스트 구조들을 가지고 연구되었다. Metal 안테나를 가지고 있는 NMOS에서 플라즈마로 인한 전하 축적으로 말미암아 10nm의 게이트 산화막에 전자 포획뿐만 아니라 정공 포획이 발생하는 것이 관측되었다. 정공포획은 전자 포획의 경우와 유사하게 transconductance(gm)의 감소를 일으키기는 하지만, 그 정도가 훨씬 적었다. 이는 플라즈마로 인한 축적이 정공 포획이 발생한 소자의 게이트 산화막에 가한 전기적 stress 가 전자 포획이 발생한 소자의 경우보다 훨씬 적었기 때문일 것이다. 이 이론은 산화막에서의 Fowler-Nordheim 전류 특성을 측정한 결과들에 의해 입증되었다.

• 한국수소및신에너지학회논문집
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• 제18권2호
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• pp.140-150
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• 2007

Thermochemical 2-step methane reforming, involving the reduction of metal oxide with methane to produce syngas and the oxidation of the reduced metal oxide with water to produce pure hydrogen, was investigated on ferrite-based metal oxide mediums. The mediums, CoFZ, CuFZ, or MnFZ, were composed of the mixture of M(M=Co, Cu or Mn)-substituted ferrite as an active component and $ZrO_2$ as a binder, respectively. The WZ medium, composed of the mixture of $WO_3$ and $ZrO_2$, was also prepared to compare. With an addition of $ZrO_2$, the surface area of the mediums was slightly increased and the sintering of active components was greatly suppressed during the reduction. The higher reactivity of the reduced mediums for water splitting was confirmed by the temperature programmed reaction. From the results of the thermochemical 2-step methane reforming, the reactivity of $CH_4$ reduction and water splitting with ferrite-based metal oxide mediums was relatively higher than that with WZ, and the order of reactivity of the mediums was MnFZ>CoFZ>CuFZ>WZ.