• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.432.2-432.2
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• 2016

A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.293-300
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• 2005

ZnO:Li epilayers were synthesized on sapphire substrates by the pulesd laser deposition (PLD) after the surface of the ZnO:Li sintered pellet was irradiated by the ArF (193 nm) excimer laser. The growth temperature was fixed at $400^{\circ}C$. The crystalline structure of epilayers was investigated by the photoluminescence (PL) and double crystal X-ray diffraction (DCXD). The carrier density and mobility of epilayers measured by van der Pauw-Hall method are $2.69\times10cm^{-3}$ and $52.137cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of epilayers obtained from the absorption spectra is well described by the Varshni's relation, $E_g(T)=3.5128eV{\cdot}(9.51\times10^{-4}eV/K)T^2/(T+280K)$. After the as-grown ZnO:Li epilayer was annealed in Zn atmospheres, oxygen and vaccum the origin of point defects of ZnO:Li has been investigated by PL at 10 K. The Peaks of native defects of $V_{zn},\;V_o,\;Zn_{int},\;and\;O_{int}$ showned on PL spectrum are classified as a donors or accepters type. We confirm that $ZnO:Li/Al_2O_3$ in vacuum do not form the native defects because ZnO:Li epilayers in vacuum existe in the form of stable bonds.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1416-1417
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• 2011

킹크효과를 억제할 수 있는 새로운 f-모양 트리플게이트 구조를 가지는 다결정실리콘 박막트랜지스터는 추가적인 공정과정 없이 제안 및 제작되었다. 이러한 다결정실리콘 박막트랜지스터의 채널에는 순차적인 횡방향 고체화(Sequential Lateral Solidification, SLS)나 CW 레이져 횡방향 결정화(CW laser Lateral Crystallization, CLC) 등과 같은 방법으로 제작된 횡방향으로 성장시킨 그레인이 있다. 이 소자의 전체적인 전류흐름은 횡방향으로 성장시킨 그레인 경계에 강력하게 영향을 받는다. f-모양 트리플게이트에는 횡방향으로 성장시킨 그레인과 평행한 방향으로 위치한 채널, 그리고 수직인 방향으로 위치한 채널이 있다. 이 소자는 f-모양 게이트 구조에서의 비대칭 이동도를 이용하여 다결정실리콘 박막트랜지스터의 킹크효과를 효과적으로 억제시킬 수 있다는 사실을 실험과 시뮬레이션을 통해 검증되었다. 우리의 실험 결과는 이 논문에서 제안된 f-모양 트리플게이트 박막트랜지스터가 기존의 박막트랜지스터와 비교할 때 더 효과적으로 킹크 효과를 감소시킬 수 있다는 것을 보여주었다. 또한 고온 캐리어 스트레스 조건에서의 신뢰성도 개선할 수 있음이 확인되었다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.8
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• pp.15-23
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• 1998

Single crystalline I $n_{x}$G $a_{1-x}$ N thin film was grwon by MOCVD on (001) sapphire substrate for the blue light emitting devices. A good quality of I $n_{0.13}$G $a_{0.87}$N/GaN heterostructure grwon above 700.deg. C was confiremed by various characterization techniques of AFM, RHEED and DC-XRD. Through PL measurement at room temperautre for the Si-Zn co-doped I $n_{x}$G $a_{a-x}$N/GaN structure grwon at 800.deg. C to obtain blue wavelength emission, 460-470 nm and 425 nm emission peak were observed, which are believed to be from donor-to-acceptor pair transition and band edge emission of In/x/G $a_{1-x}$ N, respectively. The result of PL measurement of the undoped MQW I $n_{x}$G $a_{1-x}$ N layer at low temperature confirmed that the strong MQW peak was resulted by exciton from the GAN barrier and carrier of DA pair confined into the well layer.ll layer.yer.r.

• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.281-288
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• 2005

The silica nanoparticles were used as support of catalyst, filling material, electronic assembler, thin film material, and sensor material. And, the titania nanoparticles were used as pigment, dielectric substance, sensor and photocatalyst. In this paper, the spherical composite particles of $TiO_2/SiO_2$with narrow size distribution and phase pure were synthesized by ultrasonic spray pyrolysis method from $TiOSO_4$ and colloidal silica solution. Using ultrasonic apparatus, this starting solution was vaporized to droplets, and these droplets were induced into tube furnace by carrier gas. The resulting composite powder was characterized by scanning electron microscopy, X-ray diffraction analysis, TG-DTA, in vitro sun protection factor(SPF) and BET surface area analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.93-93
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• 2009

실리콘 태양전지의 효율 향상을 위한 노력의 일환으로 결정질 실리콘 웨이퍼 표면passivation 물질 중 Atomic Layer Deposition (ALD)을 이용하여 증착한 $Al_2O_3$ 박막에 대한 관심이 증가하고 있다. 본 연구에서는 $Al_2O_3$ 박막의 증착 전 실리콘 웨이퍼의 산화막 두께에 따른 passivation 효과에 대해서 연구하였다. 실리콘 산화막은 $HNO_3$ 용액을 사용하여 화학적으로 생성시켰으며 $HNO_3$ 용액과의 반응 시간을 조절하여 실리콘 산화막의 두께를 조절하였다. 실리콘 산화막 생성 후 ALD로 $Al_2O_3$ 박막을 증착하였으며 증착 후 $N_2$ 분위기에서 annealing 하였다. Annealing 후 passivation 효과는 Quasi-Steady-State Photo Conductance를 사용하여 minority carrier의 lifetime을 측정하였다. Capacitance-Voltage measurement, Transmission Electron Microscopy, Ellipsometry를 사용하여 실리콘 산화막의 두께에 따른 $Al_2O_3$ 박막의 passivation 효과를 분석하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.129.1-129.1
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• 2011

a-Si:H/c-Si 구조의 이종접합 태양전지 전면 투명전도막으로 Indium tin oxide(ITO) 박막의 조건에 따라 태양전지 특성을 연구하였다. ITO 박막은 파우더 타겟으로 마그네트론 스퍼터링 방식으로 성막하였고, 증착 온도(Ts)에 따라 전기적, 광학적 특성을 비교, 분석하였다. 기판 증착 온도가 증가할수록 박막의 저항이 낮아지는 것으로 나타났으며 $350^{\circ}C$ 조건에서 가장 낮은 저항($34.2{\Omega}$/sq)을 보였다. 투과도 또한 기판 증착 온도가 올라갈수록 전반적인 향상을 나타냈다. a-Si:H/c-Si 기판의 MCLT(minority carrier lifetime)는 $350^{\circ}C$에서 최적($359{\mu}s$)의 결과를 나타냈다. 그 이상의 기판 온도에서는 오히려 감소하였는데, 이는 높은 온도에서의 a-Si:H/c-Si 계면의 열손상으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.257-260
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• 2007

In this study, $CuInSe_{2}$ (CISe) and $CuInZnSe_{2}$ (CIZSe) thin films were prepared on Corning 1737 glass by radio frequency (RF) magnetron sputtering from binary chalcogenide mixed powder targets. The targets were initially prepared by mixing appropriate weights of CuSe, InSe powder and various ZnSe contents. From the film bulk analysis result, it is observed that Zn concentration in the films increases proportionally with the addition of ZnSe in the sputtering targets. Under optimized conditions, CISe and CIZSe thin films grow as a chalcopyrite structure with strong (112), (220/204) and (312/116) reflections. Films are found to exhibit a high absorption coefficient of $10^{4}$ $cm^{-1}$. An increasing of optical band gap from 1.0 eV (CISe) to 1.25 eV (CIZSe) is found to be proportional with an increasing of Zn concentration as expected. All films have a p-type semiconductor characteristic with a carrier concentration in the order of 1014 $cm^{-3}$, a mobility about $10^{1}$ $cm^{2{\cdot}-1}{\cdot}s^{-1}$ and a resistivity at the range of $10^{2}-10^{6}$ W${\cdot}$m.

• Journal of Applied Reliability
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• v.9 no.2
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• pp.131-148
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• 2009

An organic light emitting diode (OLED), also light emitting polymer (LEP) and organic electro luminescence (OEL), is any light emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors. Such systems can be used in television screens, computer displays, small, portable system screens such as cell phones and PDAs, advertising, information and indication. OLEDs can also be used in light sources for general space illumination, and large-area light-emitting elements. In this paper, we develop the general guide line of the accelerated life test for assuring B10 life of AMOLED(Active Matrix Organic Light Emitting Diode) and PMOLED(Passive Matrix Organic Light Emitting Diode) which are widely used for display monitor less than 115 mm.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.28-34
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• 2002

Thin films of $Sb_{2-x}Bi_xTe_3$ (x = 0.0, 0.5, and 1.0) are grown by vacuum evaporation. XRD analysis shows the amorphous nature of the films, and the composition studies confirm the stoichiometry of the films. Microstructural parameters of the films have been calculated and used to explain the electrical and optical properties of the films. It is observed that the carrier type has changed from p- to n-type at higher concentration (x = 1.0) of Bi. The resistivity of the films decreases rapidly with the increase of Bi concentration. However, the refractive index and optical band gap of the films increase with the Bi concentration.