• 한국재료학회지
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• 제6권10호
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• pp.999-1006
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• 1996

전기화학법 중 음극환원법을 이용하여 0.005M TiCI4수용액으로부터 수화물 형태의 TiO2박막을 제조하였다. TiCI4수용액에 첨가제로 에탄올을 50vol% 첨가하여 균일한 박막을 얻을 수가 있었으며, 전류밀도와 시간에 따라서 박막의 두께와 미세구조가 변화하였다. 성장속도가 큰 조건에서 얻은 박막은 균질성의 감소로 인하여 건조과정이나 열처리 중 다량의 균열이 발생하였다. 일정한 전류밀도ㅇ에서 반응시간의 증가에 따라 박막의 두께가 직선적으로 증가하였으며, 10mA/$\textrm{cm}^2$의 전류밀도에서 3분 동안 반응시켜 약 0.7$\mu\textrm{m}$ 두께의 우수한 TiO2박막을 얻을수 있었다. 이러한 박막은 80$0^{\circ}C$에서 한 시간 열처리 한 결과, rutile 단일상으로 결정화되었다.

• 한국결정성장학회지
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• 제16권2호
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• pp.59-65
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• 2006

Al이 첨가된 ZnO(ZnO : Al) 박막과 F이 첨가된 ZnO(ZnO : F) 박막을 sol-gel 법을 이용하여 glass 기판위에 코팅하였다. 공통적으로 (002)면의 c-축 배향성을 보였지만 I(002)/[I(002) + I(101)]와 FWHM(full width at half-maximum) 값은 차이를 보였다. 특히 입자크기에 있어서는 ZnO : Al 박막에서 첨가농도가 증가함에 따라 입자크기가 감소한 반면 ZnO : F 박막에서는 F 3 at%까지 입자크기가 증가하다가 그 이후로 다시 감소하는 경향을 보였다. 진기적 성질의 측정을 위해서 Hall effect measurement를 이용하였는데 ZnO : Al 박막의 경우 Al 1 at%에서 비저항이 $2.9{\times}10^{-2}{\Omega}cm$ 이었고 ZnO : F에서는 F 3 at%에서 $3.3{\times}10^{-1}{\Omega}cm$의 값을 보였다. 또한 ZnO : F 박막은 ZnO : Al 박막에 비해서 캐리어 농도는 낮았지만(ZnO : Al $4.8{\times}10^{18}cm^{-3}$, ZnO : F $3.9{\times}10^{16}cm^{-3}$) 이동도에 있어서 상당히 큰 값(ZnO : Al $45cm^2/Vs$ ZnO:F $495cm^2/Vs$)을 보였다. 가시광선 영역에서의 평균 광투과도에 있어서는 ZnO : Al 박막에서 $86{\sim}90%$의 값을 보였지만 ZnO : F에서는 $77{\sim}85%$로 상대적으로 낮은 광투과도를 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.843-846
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• 1992

This thesis was investigated on optical-and ion-induced characteristics in positive(a-$Se_{75}Ge_{25}$) and negative (Ag/a-$Se_{75}Ge_{25}$) resists for focused-ion-beam microlithogaphy. The a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to$\sim$$10^{16}$ dose(ions/$cm^{2}$) of Ga ions. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons ($\sim$$10^{20}$ photons/$cm^{2}$). But, ion induced shift is twice as much as that in film exposed to optical radiation. This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~220$^{\circ}C$). The composition of deposited film measured by AES is consistent with that of bulk.

• 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).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.376-376
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• 2011

I-III-VI2 chalcopyrite compounds, particularly copper, indium, gallium selenide(Cu(InxGa1-x)Se2, CIGS), are effective light-absorbing materials in thin-film solar application. They are direct band-gap semiconductors with correspondingly high optical absorption coefficients. Also they are stable under long-term excitation. CIS (CIGS) solar cell reached conversion efficiencies as high as 19.5%. Several methods to prepare CIS (CIGS) absorber films have been reported, such as co-evaporation, sputtering, selenization, and electrodeposition. Until now, co-evaporation is the most successful technique for the preparation of CIS (CIGS) in terms of solar efficiency, but it seems difficult to scale up. CIS solar cells have been hindered by high costs associated with a fabrication process. Therefore, inorganic colloidal ink suitable for a scalable coating process could be a key step in the development of low-cost solar cells. Here, we will present the preparation of CIS photo absorption layer by a solution process using novel metal precursors. Chalcopyrite copper indium diselenide (CuInSe2) nanocrystals ranging from 5 to 20nm in diameter were synthesized by arrested precipitation in solution. For the fabrication of CIS photo absorption layer, the CuInSe2 colloidal ink was prepared by dispersing in organic solvent and used to drop-casting on molybdenum substrate. We have characterized the nanoparticless and CIS layer by XRD, SEM, TEM, and ICP.

• Current Photovoltaic Research
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• 제8권2호
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• pp.60-65
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• 2020

In perovskite solar cells with planar heterojunction configuration, selection of proper charge-transporting layers is very important to achieve stable and efficient device. Here, we developed solution processible Cu doped NiO_x (Cu:NiO_x) thin film as a hole-transporting layer (HTL) in p-i-n structured methylammonium lead trihalide (MAPbI₃) perovskite solar cell. The transmittance and thickness of NiO_x HTL is optimized by control the spin-coating rate and Cu is additionally doped to improve the surface morphology of undoped NiO_x thin film and hole-extraction properties. Consequently, a perovskite solar cell containing Cu:NiO_x HTL with optimal doping ratio of Cu exhibits a power conversion efficiency of 14.6%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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• pp.30-33
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• 1992

This thesis was investigated on ion-induced characteristics in a-$Se_{75}Ge_{25}$ positive and negative resists for focused-ion-beam microlithogaphy. The exposed a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to~$10_{16}$ dose of Ga+. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons(~$10^{21}$photons/cm2). This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~$220^{\circ}C$). When focused ion beams are used for direct exposure of resist over a substrate, unwanted implantation of the substrate may be an issue. A possible way to avoid this is to match the thickness of the resist to the range of ions in the resist. Thin aspect is currently under investigation.

• 센서학회지
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• 제30권5호
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• pp.279-285
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• 2021

Recently, cesium tellurium iodine (Cs₂TeI₆) has emerged as an inorganic halide perovskite material with potential application in optoelectronic devices due to its high absorption coefficient, suitable bandgap and because it consists of nontoxic and earth-abundant elements. However, studies on its fabrication process as well as photoresponse characteristics are limited. In this study, a simple and effective method is introduced for the synthesis of Cs₂TeI₆ thin films by a two-step dry process. A Cs₂TeI₆-based lateral photosensor was fabricated, and its photoresponse characteristics were explored under laser illuminations of four different wavelengths in the visible range: 405, 450, 520, and 655 nm. The initial photosensing results suggest potential application and can lead to more promising studies of Cs₂TeI₆ film in optoelectronics.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.66-69
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• 2017

In this paper, solution based Indium Zinc Oxide thin film transistors (IZO TFTs) were fabricated with PVP gate dielectric. To enhance the electrical properties, UV-O3 treatment is proposed on solution based IZO TFTs. The gate leakage current and interface trap density is compatible with conventional ZnO-based TFT with inorganic gate insulator. Especially, the UV-treated device shows improved electrical characteristics compared to the untreated device. These results can be explained by X-ray photoelectron spectroscopy (XPS) analysis, which shows that the oxygen vacancy of UV-O3 treatment is higher than that of no treatment.

• 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.