• Journal of electromagnetic engineering and science
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• 제17권3호
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• pp.126-132
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• 2017

In this study, we designed, measured, and analyzed a rearranged L-shape magnetic resonance coupling wireless power transfer (MR-WPT) system for practical applications with laptops. The typical four resonator MR-WPT (Tx part: source loop and Tx coil; Rx part: Rx coil and load loop) is difficult to apply to small-sized stationary and mobile applications, such as laptop computers, tablet-PCs, and smartphones, owing to the large volume of the Rx part and the spatial restrictions of the Tx and Rx coils. Therefore, an L-shape structure, which is the orthogonal arrangement of the Tx and Rx parts, is proposed for indoor environment applications, such as at an L-shaped wall or desk. The relatively large Tx part and Rx coil can be installed in the wall and the desk, respectively, while the load loop is embedded in the small stationary or mobile devices. The transfer efficiency (TE) of the proposed system was measured according to the transfer distance (TD) and the misaligned locations of the load loop. In addition, we measured the TE in the active/non-active state and monitor-open/closed state of the laptop computer. The overall highest TE of the L-shape MR-WPT was 61.43% at 45 cm TD, and the TE decreased to 27.9% in the active and monitor-open state of the laptop computer. The conductive ground plane has a much higher impact on the performance when compared to the impact of the active/non-active states. We verified the characteristics and practical benefits of the proposed L-shape MR-WPT compared to the typical MR-WPT for applications to L-shaped corners.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.189-189
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• 2016

Recently, many researchers have shown an increased interest in colloidal quantum dots (QDs) due to their unique physical and optical properties of size control for energy band gap, narrow emission with small full width at half maxima (FWHM), broad spectral photo response from ultraviolet to infrared, and flexible solution processing. QDs can be widely used in the field of optoelectronic and biological applications and, in particular, colloidal QDs based light emitting diodes (QDLEDs) have attracted considerable attention as an emerging technology for next generation displays and solid state lighting. A few methods have been proposed to fabricate white color QDLEDs. However, the fabrication of white color QDLEDs using single QD is very challenging. Recently, hybrid nanocomposites consisting of CdTe/ZnO heterostructures were reported by Zhimin Yuan et al.[1] Here, we demonstrate a novel but facile technique for the synthesis of CdTe/ZnO/G.O(graphene oxide) quasi-core-shell-shell quantum dots that are applied in the white color LED devices. Our best device achieves a maximum luminance of 484.2 cd/m2 and CIE coordinates (0.35, 0.28).

• 마이크로전자및패키징학회지
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• 제25권2호
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• pp.49-53
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• 2018

최근 유연 소자, 투명 소자, MEMS 소자와 같은 다양한 소자를 결합하는 시스템 집적화 기술이 많이 개발되고 있다. 이러한 다종 소자 시스템 제조 기술의 핵심 공정은 칩 또는 웨이퍼 레벨의 접합 공정, 기판 연삭 공정, 그리고 박막 기판 핸들링 기술이라 하겠다. 본 연구에서는 Si 기판 연삭 공정이 투명 박막 트랜지스터나 유연 전극 소재로 적용되는 산화주석 박막의 전기적 성질에 미치는 영향을 분석하였다. Si 기판의 두께가 얇아질수록 Si d-spacing은 감소하였고, Si 격자 내에 strain이 발생하였다. 또한, Si 기판의 두께가 얇아질수록 산화주석 박막 내 캐리어 농도가 감소하여 전기전도도가 감소하였다. 얇은 산화 주석 박막의 경우 전기전도도는 두꺼운 산화 주석 박막보다 낮았으며 Si 기판의 두께에 의해 크게 변하지 않았다.

• 한국자기학회지
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• 제14권5호
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• pp.163-168
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• 2004

나노 두께의 NiFe의 자기적 특성을 살펴보기 위해 Si(100)/ $SiO_2$(200 nm)/Ta(5 nm)/N $i_{80}$F $e_{20}$(1～15 nm)의 구조를 ICP형 헬리콘 스퍼터로 제작하였다. 제작된 시편의 자기적 물성은 SQUID를 이용하여 $\pm$50 Oe에서의 4.2K와 300K에서 각각의 M-H loop를 측정하여 자기탄성에너지 변화와 보자력을 확인하였다. 또한 SQUID로 4.2K-300K에서의 M-T curve를 통해 온도에 따른 포화자화를 두께에 따라 살펴보았다. TEM을 사용하여 제작된 시편의 각 계면간의 미세구조를 살펴보았다 나노두께의 NiFe는 3 nm 이하에서는 $B_{bulk}$=0, $B_{surf}$=-3${\times}$$10^{-7}$(J/$m^2$)의 자기 탄성계수를 보였으며, 보자력은 급격히 증가하는 것을 확인하였다. 나노 두께의 퍼말로이는 계면효과에 의해서 벌크특성과 다른 자기탄성계수, 보자력, Ms의 변화가 발생하였다. 따라서 나노급 소자를 제작할 때 이러한 변화를 고려하여 설계하여야 하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.620-621
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• 2008

Transparent electronics has been one of the key terminologies forecasting the ubiquitous technology era. Several researchers have thus extensively developed transparent oxide-based thin-film transistors (TFTs) on glass and plastic substrates although in general high voltage operating devices have been mainly studied considering transparent display drivers. However, low voltage operating oxide TFTs with transparent electrodes are very necessary if we are aiming at logic circuit applications, for which transparent complementary or one-type channel inverters are required. The most effective and low power consuming inverter should be a form of complementary p-channel and n-channel transistors but real application of those complementary TFT inverters also requires electrical- and even photo-stabilities. Since p-type oxide TFTs have not been developed yet, we previously adopted organic pentacene TFTs for the p-channel while ZnO TFTs were chosen for n-channel on sputter-deposited $AlO_x$ film. As a result, decent inverting behavior was achieved but some electrical gate instability was unavoidable at the ZnO/$AlO_x$ channel interface. Here, considering such gate instability issues we have designed a unique transparent complementary TFT (CTFTs) inverter structure with top n-ZnO channel and bottom p-pentacene channel based on 12 nm-thin nano-oxide/self assembled monolayer laminated dielectric, which has a large dielectric strength comparable to that of thin film amorphous $Al_2O_3$. Our transparent CTFT inverter well operate under 3 V, demonstrating a maximum voltage gain of ~20, good electrical and even photoelectric stabilities. The device transmittance was over 60 % and this type of transparent inverter has never been reported, to the best of our limited knowledge.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.875-881
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• 2004

Fundamental results obtained from an atomic force microscope (AFM) chemically-induced direct nano-lithography process are presented, which is regarded as a simple method for fabrication nm-scale devices such as superconducting flux flow transistors (SFFTs) and single electron tunneling transistors (SETs). Si cantilevers with Pt coating and with 30 nm thick TiO coating were used as conducting AFM tips in this study. We observed the surfaces of superconducting strip lines modified by AFM anodization' process. First, superconducting strip lines with scan size 2 ${\mu}{\textrm}{m}$${\times}$2 ${\mu}{\textrm}{m}$ have been anodized by AFM technology. The surface roughness was increased with the number of AFM scanning, The roughness variation was higher in case of the AFM tip with a positive voltage than with a negative voltage in respect of the strip surface. Second, we have patterned nm-scale oxide lines on ${YBa}-2{Cu}_3{O}_{7-x}$ superconducting microstrip surfaces by AFM conductive cantilever with a negative bias voltage. The ${YBa}-2{Cu}_3{O}_{7-x}$ oxide lines could be patterned by anodization technique. This research showed that the critical characteristics of superconducting thin films were be controlled by AFM anodization process technique. The AFM technique was expected to be used as a promising anodization technique for fabrication of an SFFT with nano-channel.

• International Journal of Internet, Broadcasting and Communication
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• 제10권1호
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• pp.71-76
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• 2018

The technology convergence of television, communication, and computing devices enables the rich social and entertaining experience through Smart TV in personal living space. The powerful smart TV computing platform allows to provide various user interaction interfaces like IR remote control, web based control, body gesture based control, etc. The presently used smart TV interaction user control methods are not efficient and user-friendly to access different type of media content and services and strongly required advanced way to control and access to the smart TV with easy user interface. This paper propose the optical wireless communication (OWC) based remote controller design for Smart TV using smart device Flashlights. In this approach, the user smart device act as a remote controller with touch based interactive smart device application and transfer the user control interface data to smart TV trough Flashlight using visible light communication method. The smart TV built-in camera follows the optical camera communication (OCC) principle to decode data and control smart TV user access functions according. This proposed method is not harmful as radio frequency (RF) radiation does it on human health and very simple to use as well user does need to any gesture moves to control the smart TV.

• 대한전자공학회논문지SD
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• 제43권4호
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• pp.23-30
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• 2006

본 연구에서는 나노 스케일 MuGFET(Mutiple-Gate FETs)의 단채널 효과와 corner effect를 3차원 시뮬레이션을 통하여 분석하였다. 문턱전압 모델을 이용하여 게이트 숫자(Double-gate=2, Tri-gate=3, Pi-gate=3.14, Omega-gate=3.4, GAA=4)를 구하였으며 추출된 게이트 숫자를 이용하여 각각의 소자 구조에 맞는 natural length($\lambda$)값을 얻을 수 있었다. Natural length를 통하여 MuGFET의 단채널 효과를 피할 수 있는 최적의 소자 구조(실리콘 두께, 게이트 산화막의 두께 등)를 제시 하였다. 이러한 corner effect를 억제하기 위해서는 채널 불순물의 농도를 낮게 하고, 게이트 산화막의 두께를 얇게 하며, 코너 부분을 약 17%이상 라운딩을 해야 한다는 것을 알 수 있었다.

• 한국세라믹학회지
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• 제51권3호
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• pp.208-217
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• 2014

$La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2-x}Zn_xO_{2.8}$(LSGMZ, X=0-0.05) was prepared using a solid state reaction method. Two secondary phases ($LaSrGaO_4$ and $LaSrGa_3O_7$) of powders were identified by X-ray diffraction analysis. The relative amount of these secondary phases depended on the calcination conditions (temperature and time) and Zn content. The sintering density of LSGMZ was enhanced by increasing the Zn content and calcination temperature at the low sintering temperatures ($1250-1300^{\circ}C$). The relationship between the sintering density of LSGMZ and the synthesis conditions was discussed considering the phase analysis results.

• 폴리머
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• 제29권4호
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• pp.418-421
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• 2005

본 연구에서는 나노/마이크로 소자 및 MEMS 제작에 활용가능하고 또한 수십 마이크로미터 크기의 3차원 곡면을 가진 형상을 제작하기 유리한 이광자 광중합을 이용한 다중조사 복셀 매트릭스 스캐닝법(multi-exposure voxel matrix scanning method)에 의한 나노 복화공정을 개발하였다. 이 공정을 통하여는 높이에 따라 14가지의 색을 가진 등고선으로 표현된 3차원 자유곡면 형상을 적층방식이 아닌 단일 층으로 3차원으로 제작할 수 있다. 여기서 수광각도가 1.25인 집광렌즈를 사용하여 레이저의 조사시간에 따라 1.2 um에서 6.4 um까지 변하는 복셀의 높이 차이를 이용하여 3차원 곡면 제작이 가능하다. 본 연구의 유용성을 검토하기 위하여 몇 가지 3차원 곡면형상을 초미세 입체 패터닝 공정에서 사용하는 일반적인 적층방식을 사용하지 않고 단층으로 제작하여 시간을 단축하였다.