• 한국전기전자재료학회논문지
• /
• 제25권3호
• /
• pp.236-240
• /
• 2012

Limiting thermal exposure time using rapid thermal processing(RTP) has emerged as promising simplified process for manufacturing of solar cell in a continuous way. This paper reports the simplification of co-firing using RTP. Actual temperature profile for co-firing after screen printing is a key issue for high-quality metal-semiconductor contact. The plateau time during the firing process were varied at $450^{\circ}C$ for 10~16 sec. Glass frit in Ag paste etch anti-reflection layer with plateau time. Glass frit in Ag paste is important for the Ag/Si contact formation and performances of crystalline Si solar cell. We achieved 17.14% efficiency with optimum conditions.

• 융복합기술연구소 논문집
• /
• 제8권1호
• /
• pp.1-4
• /
• 2018

In this study, design and manufacture of LFR (Linerar Fresnel Reflector) system was performed for solar thermal absorption cooling. The LFR system was designed considering the expansion and convenience to be installed according to the cooling capacity of the applicable building. Twelve LFR modules with a total reflection area of $204m^2$ were installed. The automatic tracking system was applied to track the sun during the daytime.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.47.2-47.2
• /
• 2010

텍스쳐링은 태양전지 표면에 어떠한 "요철"을 만들거나 거칠게 만들어 빛이 반사되는 면을 최대한 늘리는 구조를 만드는 공정으로 anti-reflection coating과 같이 태양전지에 입사되는 빛의 반사를 최소화 시키는데 그 목적이 있다. 단결정 실리콘 웨이퍼의 경우 표면에 피라미드 구조를 형성하는 것이 텍스쳐링 공정인데, 수산화칼륨과 이소프로필 알콜의 혼합용액으로 인해 식각되는 웨이퍼 표면이 작은 "pellet"으로 시작하여 그 크기와 수가 점점 증가하여 피라미드의 형태를 갖춰가는 방법으로 진행된다. 이와 같은 텍스쳐링 공정의 성패를 좌우하는 가장 큰 이슈는 "식각률"이다. 이 식각률에 영향을 주는 인자는 그 종류가 많으나 온도, 시간, KOH 농도(비율) 세 가지로 압축할 수 있다. 또 다른 요소인 Bath 내 chemical flow 및 Bubbling은 정량화하기 어렵고, 이용 장비가 변경되면 공정 조건 또한 변경되기 때문이다. 본 논문에서는 단결정 실리콘 웨이퍼에 적용하는 최적의 텍스쳐링 조건을 수립하기 위해 주요 공정변수를 온도, 시간, KOH 농도로 정하고, 다구치 방법을 사용하여 주요공정변수의 범위를 정하였으며, 보다 완벽한 강건설계를 위하여 3인자 3수준의 망소특성으로 설계하였다. 그 결과 반사율과 식각률의 경향성을 파악하여 주요 변수들 간 최적의 조건을 찾을 수 있었다.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
• /
• pp.154-157
• /
• 2011

Hydrogenated silicon nitride deposited by LF-PECVD is commonly used for anti-reflection coating and passivation in silicon solar cell fabrication. The deposition of the optimized silicon nitride on the surface is elemental in crystalline silicon solar cell. In this work, the carrier lifetimes were measured while the thicknesses of $SiN_x$ were changed from 700 ${\AA}$ to 1150 ${\AA}$ with the gas flow of $SiH_4$ as 40 sccm and $NH_3$ as 120 sccm,. The carrier lifetime enhanced as the thickness of $SiN_x$ increased due to improved passivation effect. To study the characteristics of $SiN_x$ with various gas ratios, the gas flow of $NH_3$ was changed from 40 sccm to 200 sccm with intervals of 40 sccm. The thickness of $SiN_x$ was fixed as 1000 ${\AA}$ and the gas flow of $SiH_4$ as 40 sccm. The refractive index of SiNx and the carrier lifetime were measured before and after heat treating at $650^{\circ}C$ to investigate their change by the firing process in solar cell fabrication. The index of refraction of SiNx decreased as the gas ratios increased and the longest carrier lifetime was measured with the gas ratio $NH_3/SiH_4$ of 3.

• 한국표면공학회지
• /
• 제49권3호
• /
• pp.301-306
• /
• 2016

The effects of nanotexturing and post-etching on the reflection and quantum efficiency properties of diamond wire sawn (DWS) multicrystalline silicon (mc-Si) solar cell have been investigated. The chemical solutions, which are acidic etching solution (HF-$HNO_3$), metal assisted chemical etching (MAC etch) solutions ($AgNO_3$-HF-DI, HF-$H_2O_2$-DI) and post-etching solution (diluted KOH at $80^{\circ}C$), were used for micro- and nano-texturing at the surface of diamond wire sawn (DWS) mc-Si wafer. Experiments were performed with various post-etching time conditions in order to determine the optimized etching condition for solar cell. The reflectance of mc-Si wafer texturing with acidic etching solution showed a very high reflectance value of about 30% (w/o anti-reflection coating), which indicates the insufficient light absorption for solar cell. The formation of nano-texture on the surface of mc-Si contributed to the enhancement of light absorption. Also, post-etching time condition of 240 s was found adequate to the nano-texturing of mc-Si due to its high external quantum efficiency of about 30% at short wavelengths and high short circuit current density ($J_{sc}$) of $35.4mA/cm^2$.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.686-686
• /
• 2013

Crystalline silicon solar cell is a semiconductor device that converts light into electrical energy. Screen printing is commonly used to form the front/back electrodes in silicon solar cell. Screen printing method is convenient but usually shows high resistance and low aspect ratio, which cause the efficiency decrease in crystalline silicon solar cell. Recently the plating method is applied in c-Si solar cell to reduce the resistance and improve the aspect ratio. In this paper, we investigated the effect of additional electroless Ag plating into screen-printed c-Si solar cell and compared their electrical properties. All wafers used in this experiment were textured, doped, and anti-reflection coated. The electrode formation was performed with screen-printing, followed by the firing step. Aften then we carried out electroless Ag plating by changing the plating time in the range of 20 sec~5 min and light intensity. The light I-V curve and optical microscope were measured with the completed solar cell. As a result, the conversion efficiency of solar cells was increased mainly due to the decreased series resistance.

• 한국산학기술학회논문지
• /
• 제15권7호
• /
• pp.4463-4468
• /
• 2014

태양광 모듈 효율의 증가를 위해 렌즈나 반사판 등을 이용한 집광 시스템 개발이 활발하게 진행되고 있으며, 집광장치는 일반적으로 렌즈를 사용하거나 고집속비의 광학장치를 이용하여 태양광 추적형으로 설계하여 고집속화를 추구하고 있다. 그러나 집속비에 비례하여 열로 소산되는 에너지 밀도가 증가하므로, 고집속에 따른 태양전지 온도상승에 의한 태양전지 효율 저하를 방지하기 위해 집광장치의 냉각에 유의해야 한다. 본 논문에서는 이러한 여러 가지 제약 조건을 피하여, 저가격의 반사형 광학장치를 이용한 경제적인 저집광형 태양광 모듈 시스템을 연구 개발하였다. 일반모듈에 저집광장치를 사용하여 태양광 모듈의 발전효율을 증대 시키면서 집광으로 인해 발생하는 열을 냉각장치를 통해 방출하였다. 제안된 저집광형 냉각장치(MCS, Micro Cooling System)의 특징은 모세관력에 의한 자연 순환 방식으로서 외부 동력원이 불필요하며, 유체 상변환시의 잠열을 이용함으로써 고성능 냉각 구현이 가능하다. 117W 태양광 모듈에 반사판을 설치하고 냉각장치가 있는 모듈과 냉각장치가 없는 모듈을 비교 하였다. 냉각장치를 설치한 모듈에서의 발전량이 28% 증가하였다.

• 전기의세계
• /
• 제25권5호
• /
• pp.63-69
• /
• 1976

Among various types of photo-electric energy conversion element which can transfer solar energy into electric energy through the photo voltaic effect, Si solar cells were investigated on photoelectric characteristics, improvements of its efficiency and economical evaluation for its production cost. To study the above subjects, we decided best conditions on fabricating of thin film Si solar cell by epitaxial growth and knew that the thin solar cell by epitaxial growth was more efficient than that by diffusion process. And also higher photo voltaic output was obtained as a effect of SiO as antireflection coating by several methods, i.e. vacuum evaporating techniques of electrode to decrease the contact resistance and to form best ohmic contact, and concentration techniques of sun's ray by lenz or both-sided illumination through special structure for reflection using mirrors.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
• /
• pp.5-6
• /
• 2006

There are typically applied on both rear and front sides of electrical contacts to the solar cell. The front contact formation is particularly sensitive to many parameters. Accordingly patterning of front grid line is an important factor of solar cells. This paper describe the electrical conversion efficiency, inclusive of shading loss that gives various spacing between front metal grid lines. In experiments with variation of spacing. It was verified that the wide spacing of grid fingers could increase the series resistance, also the narrow spacing of grid fingers also implies a grid with a higher density of grid fingers. The sunlight of incidence was more of reflection by grid fingers. In result, the short circuit current, which contribute to conversion efficiency was decreased, because maximum power input was reduced and increase the series resistance.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
• /
• pp.289-290
• /
• 2006

We report a study of Zn(S)Se/GaAs heterojunction solar cells grown by molecular beam epitaxy (MBE). Zn(S)Se/GaAs heterostructures prepared under different conditions were characterized in-situ by reflection high-energy electron diffraction (RHEED). Structural and electrical properties were investigated with double crystal X-ray diffraction and current-voltage characteristics, respectively. The fabricated $n-ZnS_{0.07}Se_{0.93}/p-GaAs$ solar cell (SC #2) exhibited open circuit voltage($V_{oc}$) of 0.37 V, short circuit current($I_{sc}$) of $1.7{\times}10^{-2}$ mA, fill factor of 0.62 and conversion efficiency of 7.8 % under 38.5 $mW/cm^2$ illumination.