• 한국응용과학기술학회지
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• 제33권3호
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• pp.483-491
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• 2016

나노실리카가 코팅된 유리 표면은 나노실리카 표면에 존재하는 친수성 수산기로 인해 방담성이 매우 증가하나, 실외에 설치된 유리에 코팅된 경우는 비에 의해 씻겨 나가 방담 특성의 내구성이 급격히 감소한다. 또한 나노실리카가 코팅된 유리 표면의 토폴로지는 광투과율 또는 반사방지 특성을 좌우하는 매우 중요한 인자이다. 이러한 나노실리카 코팅의 특성에 관한 내구성을 향상시키기 위하여 가교제로 테트라에틸오르소실리케이트 (TEOS)를 사용하여 나노실리카 (Ludox) 현탁액으로 친수성 나노실리카피막을 제조하였다. 산성 또는 염기성 수용액 중에서의 TEOS의 가수 분해 최적 조건도 물에 대한 접촉각 측정을 통하여 조사하였다. pH=4의 산성 조건에서 1.5 wt% 나노실리카-TEOS 코팅액으로 얻은 최종 투명한 친수성 코팅층은 매우 향상된 친수성에 대한 내구성뿐만 아니라, 코팅하지 않은 유리에 비해 약 2 % 포인트 정도 높은 가시광투과율을 나타내었다.

• 한국광학회지
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• 제6권4호
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• pp.259-265
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• 1995

국내 민수용으로 유통되고 있는 20여종의 무반사 안경렌즈들을 선정하여 광학적 특성을 분석하였다. 분광광도계를 사용하여 측정한 반사특성과 투과특성을 렌즈의 굴절력, 각 무반사층들 및 렌즈기층에 의한 영향과 연결시켜 분석하였다. 흡수단 근방에서의 겉보기 흡수스펙트럼은 기층물질에 따라 결정되며 400-700nm의 파장대역에서 대부분의 시료들의 겉보기 흡수스펙트럼과 반사스펙트럼은 강한 양의 상관관계를 보여준다. 예외적으로 기층에 의한 흡수가 큰 렌즈들은 상관관계가 약해지며 이와 같은 기층에 의한 흡수는 무반사 특성에 부정적인 효과를 가진다. 또한 국내에서 제작되는 $SiO_2/TiO_2/SiO_2/ZrO_2/Cr$ 다층박막층을 c-Si 기층위에 성장시키면서 각 단계별로 ex-situ 분광타원해석법으로 분석하여 $TiO_2$ 박막과 $ZrO_2$ 박막의 조밀도가 80% 정도에 불과하며 박막이 두꺼원 짐에 따라 박막에 수직한 방향으로 균일하지 않음을 확인하였다. 마지막으로 실시간, in-suti 측정을 바탕으로하여 엄밀한 사양이 요구되는 다층박막, 초격자박막 등을 재현성있게 성장시킬 수 있는 가능성에 대해 토의하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.977-980
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• 2004

본 논문에서는 저가 고효율 태양전지를 제작하기 위하여 p형 다결정 실리콘 기판을 사용하여 수산화 칼륨(KOH)이 포함된 용액에 Saw damage 과정 후 불산이 함유된 용액에 전기화학적 양극산화 과정으로 실리콘 웨이퍼 표면에 요철을 형성하여 다공성 실리콘을 형성 하였다. 본 논문은 전기화학적 에칭방법으로 기존의 진공장비로 제작된 반사방지막의 반사율만큼 감소된 다공성 실리콘 반사방지막을 형성하였다. 전자빔 증착기(e-beam evaporator)로 단층으로 형성된 $TiO_2$의 반사방지막은 400-1000 nm의 파장 범위에서 4.1 %의 평균 반사율을 가졌으며, 양극산화과정으로 형성된 다공성 실리콘은 400-1000 nm의 파장의 범위에서 4.4 %의 평균 반사율을 가졌다. 본 연구는 태양전지의 반사방지막 형성을 기존의 제작 방법보다 간단하고 저렴한 방법으로 접근하여 태양전지의 변환효율을 상승하는데 목적을 두었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.24.1-24.1
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• 2010

In practical operation, the exposed surfaces may get dirty thus degrade the performance of devices. So the combination of self cleaning and antireflection is very desirable for use in outdoor photovoltaic and displaying devices, self cleaning windows and car windshields. For the purpose of self cleaning, the surface needs to be either superhydrophobic or superhydrophilic. However, in practice AR in the visible region and self cleaning are a pair of competitive properties. To satisfy the requirements for superhydrophobic or superhydrophilic surfaces, high surface roughness is required. But it usually cause severely light scattering. Photo-responsive coatings (TiO2, ZnO etc.) can lead to superhydrophilic. However, the refractive indices are high. Thus for porous structure, controlling pore size in the underwavelength scale to reduce the light scattering is very crucial for highly transparent and self cleaning antireflection coating. Herein, we demonstrate a simple method to make high performance broadband antireflection layer on the glass surface, by "carving" the surface by hot alkali solution. Etched glass has superhydrophilic surface. By chemical modification, it turns to superhydrophobic. Enhanced transparency (up to 97%) in a broad wavelength range was obtained by short time etching. Also antifogging effect has been demonstrated, which may offer advantage for devices working at high humidity environment or underwater. Compositional dependence of the properties was observed by comparing three different commercially available glasses.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.1039-1042
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• 2001

A method for designing antireflection (AR) and antistatic (AS) films by the use of conducting polymer as an electrically conductive transparent layer is proposed. The conducting AR film is composed of four-layer with alternating high and low refractive index layer: silicon dioxide (n=1.44) and titanium dioxide (n=2.02) prepared at low temperature by sol-gel method are used as the low and high refractive index layer, respectively. The 3,4-polyethylenedioxythiophene (PEDOT) which has the sheet resistance of 10$^4$$\Omega$/$\square$ is used as a conductive layer. Optical constant of ARAS film was measured by the spectroscopic ellipsometer and from the measured optical constants the spectral properties such as reflectance and transmittance were simulated in the visible region. The reflectance of ARAS films on glass substrate was below 0.8 %R and the transmittance was higher than 95 % in the visible wavelength (400-700 nm). The measured AR spectral properties was very similar to its simulated results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.149-149
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• 2010

The double-layer antireflection (DLAR) coatings have significant advantages over single-layer antireflection (SLAR) coatings. This is because they will be able to cover a broad range of the solar spectrum which would enhance the overall performance of solar cells. Moreover films deposited at high frequency are expected to show excellent and UV-stable passivation in the refractive index that we adopted. In this work, we present a novel DLAR coating using SiNx:H thin films with refractive indices 1.9 and 2.3 as the top and bottom layers. This approach is cost effective when compared to earlier DLAR coatings with two different materials. SiNx:H films were deposited by Plasma enhanced chemical vapor deposition (PECVD) technique using $SiH_4$, $NH_3$ and $N_2$ gases with flow rates 20~80sccm, 200sccm and 85 sccm respectively. The RF power, plasma frequency and substrate temperature for the deposition were 300W, 13.56 MHz and $450^{\circ}C$, respectively. The optimum thickness and refractive indices values for DLAR coatings were estimated theoretically using Macleod simulation software as 82.24 nm for 1.9 and 68.58 nm for 2.3 respectively. Solar cells were fabricated with SLAR and DLAR coatings of SiNx:H films and compared the cell efficacy. SiNx:H> films deposited at a substrate temperature of $450^{\circ}C$ and that at 300 W power showed best effective minority carrier lifetime around $50.8\;{\mu}s$. Average reflectance values of SLAR coatings with refractive indices 1.9, 2.05 and 2.3 were 10.1%, 9.66% and 9.33% respectively. In contrast, optimized DLAR coating showed a reflectance value as low as 8.98% in the wavelength range 300nm - 1100nm.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.498-505
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• 1996

In the present work, we have developed the simulator to optimize the process conditions of the AR(antireflection) and HR(high-reflection) coatings for the high power laser diode. The simulator can run on the PC. After making the simple optical model, we establish the Maxwell equations for the model by the operator conversion. By using the Mathematica, we derive a matrix for the multilayer system by applying the equations to the model and optimize the AR and HR coating process conditions by obtaining the reflection rate from the matrix. We also prove the validity of the simulator by comparing the simulation with the characteristics of the laser diode which is AR and HR coated according to the optimized conditions.

• ETRI Journal
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• 제31권6호
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• pp.675-679
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• 2009

$Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권10호
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• pp.447-450
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• 2003

This paper presents a process optimization of antireflection (AR) coating on crystalline Si solar cells. Theoretical and experimental investigations were performed on a double-layer AR (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. RF sputter grown CeO$_2$ film showed strong dependence on a deposition temperature. The CeO$_2$ deposited at 40$0^{\circ}C$ exhibited a strong (111) preferred orientation and the lowest surface roughness of 6.87 $\AA$. Refractive index of MgF$_2$ film was measured as 1.386 for the most of growth temperature. An optimized DLAR coating showed a reflectance as low as 2.04% in the wavelengths ranged from 0.4${\mu}{\textrm}{m}$ to 1.1${\mu}{\textrm}{m}$. We achieved the efficiencies of solar cells greater than 15% with 3.12% improvement with DLAR coatings. Further details on MgF$_2$, CeO$_2$ films, and cell fabrication parameters are presented in this paper.

• 전자공학회논문지A
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• 제32A권11호
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• pp.44-51
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• 1995

Homogeneous, compositionally graded, and superlattice-like silicon oxynitride(SiON) dielectric layers, with the refractive index varying from 1.46 to 2.05 as a function of film thickness, were grown by computer-controlled plasma-enhanced chemical vapor deposition (PECVD) using silane, nitrogen, and nitrous oxide reactant gases. An antireflection(AR) coating and thin-film electroluminescent(TFEL) devices with multiple dielectrics were designed and fabricated using real time control of reactant gases of the PECVD system.