• Carbon letters
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• 제13권1호
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• pp.17-22
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• 2012

Currently, graphene is a topic of very active research in fields from science to potential applications. For various radio-frequency (RF) circuit applications including low-noise amplifiers, the unique ambipolar nature of graphene field-effect transistors can be utilized for high-performance frequency multipliers, mixers and high-speed radiometers. Potential integration of graphene on Silicon substrates with complementary metal-oxide-semiconductor compatibility would also benefit future RF systems. The future success of the RF circuit applications depends on vertical and lateral scaling of graphene metal-oxide-semiconductor field-effect transistors to minimize parasitics and improve gate modulation efficiency in the channel. In this paper, we highlight recent progress in graphene materials, devices, and circuits for RF applications. For passive RF applications, we show its transparent electromagnetic shielding in Ku-band and transparent antenna, where its success depends on quality of materials. We also attempt to discuss future applications and challenges of graphene.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.190-192
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• 2007

A neutral beam system has been developed to produce hyperthermal neutral beams composed of indium, tin, and oxygen atoms. Using these hyper thermal neutral beams with energies in the range of tens of eV, high quality indium-tin oxide (ITO) thin films have been obtained on glass substrates at room temperature. The optical transmittance of the films is higher than 85% at a wavelength of 550 nm and the electrical resistivity is lower than $1{\times}10^{-3}{\Omega}cm$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.441-442
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• 2007

We deposited nickel oxide(NiO) thin films on silicon(Si) substrates at Room temperature and $500^{\circ}C$ using a nickel target by reactive DC and RF sputtering. In addition, we anneal to NiO thin films deposited at room temperature. Using spectroscopic eillipsometry, we obtained optical characteristics of every films. We discussed relations of the optical and structural properties of NiO thin films with the oxygen flow rate, substrate temperature and annealing temperatures. Refraction was decreased and defect was increased when NiO thin films was annealed. We also analyzed the electrical characteristics of NiO films which deposited DC and RF sputtering method.

• 한국전기전자재료학회논문지
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• 제24권9호
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• pp.710-712
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• 2011

In this study, we fabricate resistive switching random access memory (ReRAM) devices constructed with a Al/$HfO_2$/ITO structure on glass substrates and investigate their memory characteristics. The hafnium oxide thin film used as a resistive switching layer is sputtered at room temperature in a sputtering system with a cooling unit. The Al/$HfO_2$/ITO device exhibits bipolar resistive switching characteristics, and the ratio of the high resistance (HRS) to low resistance states (LRS) is more than 60. In addition, the resistance ratio maintains even after $10^4$ seconds.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.372-372
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• 2007

Titanium oxide nanotube arrays were fabricated by the anodization of pure titanium thin film deposited at $500^{\circ}C$ on silicon substrates. The titania nanotubes were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 30 V. $TiO_2$ nanotube array with a small pore diameter of 40 nm and long titanium oxide layer of $4\;{\mu}m$ was obtained. The $TiO_2$ nanotube array was used as a porous electrode for quartz crystal microbalance (QCM). Nanoporous morphology of electrode will increase the sensitivity of microbalance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.444-445
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• 2007

Aluminum-doped zinc oxide (AZO) films are attractive materials as transparent conductive electrode because they are inexpensive, nontoxic and abundant element compared with indium tin oxide (ITO). AZO films have been deposited on glass (coming 1737) substrates by RF magnetron sputtering system. An ultrathin layer of nickel oxide (NiO) was deposited on the AZO anode to enhance the hole injections in organic light-emitting diodes (OLED). The current density-voltage and luminescence-voltage properties of devices were studied and compared with ITO device.

• 한국초전도ㆍ저온공학회논문지
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• 제20권4호
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• pp.20-25
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• 2018

Niobium nitride (NbN) superconducting thin films with the thickness of 100 and 400 nm have been deposited on the surfaces of silicon oxide/silicon substrates using a sputtering method. Their superconducting properties have been evaluated in terms of the transition temperature, critical magnetic field, and critical current density. In addition, the NbN films were patterned in a line with a width of $10{\mu}m$ by a reactive ion etching (RIE) process for their characterization. This study proves the applicability of the standard complementary metal-oxide-semiconductor (CMOS) process in the fabrication of superconducting thin films without considerable degradation of superconducting properties.

• Corrosion Science and Technology
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• 제7권1호
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• pp.50-60
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• 2008

The majority of the described experimental results deal with relatively pure aluminium. Variations were made in the pretreatment of the aluminum substrates and an investigation was performed on the resulting changes in oxide layer composition and chemistry. Subsequently, the bonding behavior of the surfaces was investigated by using model adhesion molecules. These molecules were chosen to represent the bonding functionality of an organic polymer. They were applied onto the pretreated surfaces as a monolayer and the bonding behavior was studied using infrared reflection absorption spectroscopy. A direct and clear relation was found between the hydroxyl fraction on the oxide surfaces and the amount of molecules that subsequently bonded to the surface. Moreover, it was found that most bonds between the oxide surface and organic functional groups are not stable in the presence of water. The best performance was obtained using molecules, which are capable of chemisorption with the oxide surface. Finally, it was found that freshly prepared relatively pure aluminum substrates, which are left in air, rapidly lose their bonding capacity towards organic functional groups. This can be attributed to the adsorption of contamination and water to the oxide surface. In addition the adhesion of a typical epoxy-coated aluminum system was investigated during exposure to water at different temperatures. The coating was found to quite rapidly lose its adhesion upon exposure to water. This rapid loss of adhesion corresponds well with the data where it was demonstrated that the studied epoxy coating only bonds through physisorptive hydrogen bonding, these bonds not being stable in the presence of water. After the initial loss the adhesion of the coating was however found to recover again and even exceeded the adhesion prior to exposure. The improvement could be ascribed to the growth of a thin oxyhydroxide layer on the aluminum substrate, which forms a new, water-stable and stronger bond with the epoxy coating. Two routes for improvement of adhesion are finally decribed including an interphasial polymeric thin layer and a treatment in boiling water of the substrate before coating takes place. The adhesion properties were finely also studied as a function of the Mg content of the alloys. It was shown that an enrichment of Mg in the oxide could take place when Mg containing alloys are heat-treated. It is expected that for these alloys the (hydr)oxide fraction also depends on the pre-treatment and on the distribution of magnesium as compared to the aluminium hydroxides, with a direct impact on adhesive properties.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.301.2-301.2
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• 2016

Metal-oxide thin-film transistors (TFTs) have gained a considerable interest in transparent electronics owing to their high optical transparency and outstanding electrical performance even in an amorphous state. Also, these metal-oxide materials can be solution-processed at a low temperature by using deep ultraviolet (DUV) induced photochemical activation allowing facile integration on flexible substrates [1]. In addition, high-dielectric constant (k) inorganic gate dielectrics are also of a great interest as a key element to lower the operating voltage and as well as the formation of coherent interface with the oxide semiconductors, which may lead to a considerable improvement in the TFT performance. In this study, we investigated the electrical properties of solution-processed high-k strontium-doped AlOx (Sr-AlOx) gate dielectrics. Using the Sr-AlOx as a gate dielectric, indium-gallium-zinc oxide (IGZO) TFTs were fabricated and their electrical properties are analyzed. We demonstrate IGZO TFTs with a 10-nm-thick Sr-AlOx gate dielectric which can be operated at a low voltage (~5 V).

• 공업화학
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• 제9권2호
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• pp.214-219
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• 1998

초음파분무 열분해에 의하여 유리 기판 위에 투명전도성 산화주석막을 증착하였다. 증착변수가 산화주석막의 전기저항, 광투과도, 결정구조 및 두께에 미치는 영향을 조사하였다. 증착시간과 염화주석(IV)의 농도가 증가함에 따라, 증착된 산화주석막의 전기저항과 가시선 및 근적외선 영역에서의 광투과도가 감소함을 보여주었다. 공기중에서 열처리온도가 증가하면, 증착된 산화주석막은 전기저항과 광투과도가 증가함을 나타냈다. 본 연구결과는 초음파분무열분해가 단일과정으로서 양질의 투명전도막을 효율적으로 제조할 수 있는 유망한 증착기술임을 암시한다.