• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.115.1-115.1
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• 2011

최근 기본적인 pin 구조의 박막 cell 에서 i layer를 최적화 시키는 방안으로 double layer 구조가 많이 연구되고 있다. 본 연구에서는 ASA(Advanced Semicon ductor Analysis) simulation을 이용하여 i-double layer 최적화에 대한 연구를 진행해 보았다. 두께 150/150nm의 i double layer의 band gap 가변을 한 simulation 결과를 보았을 때, p쪽의 band gap이 상승하면서 intrinsic layer 내의 field가 증가하여 recombination center가 감소하였으나 FF의 감소가 있었다. n쪽의 band gap을 상승 시켰을때 n/i 쪽 field 증가로 Voc가 상승되어 초기 효율이 증가하였으나 intrinsic layer내의 field가 감소하여 recombination center가 오히려 증가하였다. 결과적으로 electric field와 효율을 동시에 고려했을 때 두께 300nm, 1.75의 band gap을 가지는 single layer 보다 150/150nm두께에 1.8/1.7 또는 1.8/1.75의 bandgap을 가지는 double layer를 사용하였을 때 보다 높은 효율을 얻을 수 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.2
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• pp.65-72
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• 2012

Aluminum induced crystallization of amorphous silicon was attempted by the aluminum substrate. To avoid the layer exchange between silicon and aluminum layer, Ni layer was deposited between these two layers by sputtering. To obtain the bigger grain of the crystalline silicon, wet blasted silica layer was employed as windows between the nickel and a-Si layer. Ni obtained after the annealing treatment at $520^{\circ}C$ was found to be a promising material for the diffusion barrier between silicon and aluminum. One way to obtain bigger grain of crystalline silicon layer applicable to solar cell of higher performance was envisioned in this investigation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.1019-1023
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• 2012

In this research, a novel direct-aluminum-heating-induced crystallization method was developed for the purpose of application to solar cells. By applying a constant current of 3 A to an aluminum thin film, a 200-nm-thick amorphous silicon (a-Si) thin film with a size of $1cm{\times}1cm$ can be crystallized into a polycrystalline silicon (poly-Si) thin film within a few tens of seconds. The Raman spectrum analysis shows a peak of 520 $cm^{-1}$, which verifies the presence of poly-Si. After removing the aluminum layer, the poly-Si thin film was found to be porous. SIMS analysis showed that the porous poly-Si thin film was heavily p-doped with a doping concentration of $10^{21}cm^{-3}$. Thermal imaging shows that the crystallization from a-Si to poly-Si occurred at a temperature of around 820 K.

• Solar Energy
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• v.8 no.1
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• pp.68-73
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• 1988

In the glass/TCO/p-i-n a-Si/Al type of amorphous silicon solar cell, the effects on solar cell efficiency and metastability for the various kinds of TCO analyzed by SAM and ESCA, which was used to measure the diffusion profiles of In and Sn and the Fermi energy shifts in the TCO/p interface respectively. Indium which diffused into a-Si p-layer did not have any significant effects on the Fermi level shift of p-layer when the content of $B_2H_6/SiH_4$ in p-layer was at 1 gas%. The cell fabricated on $SnO_2$ turned out to have the best cell photovoltaic characteristics. ITO fabricated by electron beam deposition system, which was shown to have the greatest rate of diffusion of Indium in ITO/p interface produced the worst metastability among the cells tested.

• Solar Energy
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• v.7 no.1
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• pp.30-34
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• 1987

Experimental results are discussed concerning temperature effects from $25^{\circ}C$ to $100^{\circ}C$ on amorphous silicon solar cells. N-I-P hydrogenated amorphous silicon solar cells are fabricated on stainless steel and indium tin oxide glass substrates. The open circuit voltage, short circuit current, fill factor and conversion efficiency have been measured under AM1 condition as a function of temperature. The open circuit voltage decreased by $2.6mV/^{\circ}C$ while the short circuit current increases with increased temperature. The conversion efficiency is almost independent of temperature which is contrary to widely using single crystalline solar cells of which efficiencies decrease with increasing temperature.

• Solar Energy
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• v.7 no.1
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• pp.35-41
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• 1987

This paper presents a comprehensive computer simulation of hydrogenated amorphous p-i-n silicon solar cells. The physical mechanism governing solar cell operation has been modeled and solved numerically by Runge-Kutta-Gill method. Effects of gap state density, dopant impurity, diffusion length and interface recombination velocity on solar cell performance are investigated. Numerical results show that the electric field in i-region is not uniform but depends strongly on voltage and position. A rather poor fill factor may be due to the electric field variation and short diffusion length. It is found out that the life time should be improved in order to increase a fill factor and a conversion efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.450-451
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• 2008

Amorphous silicon Solar cell has n-i-p structure in general, and each layer's thickness and doping concentration are very important factors which are as influential on efficiency of salar cell. Using AFORS HET simulation to get the high efficiency, by adjusting n layer's thickness and doping concentration, p layer's doping concentration. The optimized values are a-Si:H(n)'s thickness of 1nm, a-Si:H(n)r's doping concentration of $2\times10^{20}cm^{-3}$, a-Si:H(p+)r's doping concentration of $1\times10^{19}cm^{-3}$. After optimization, the solar cell shows $V_{oc}$=679.5mV, $J_{sc}$=39.02mA/$cm^2$, FF=83.71%, and a high Efficiency=22.21%. Though this study, we can use this study for planning or manufacturing solar cell which has high efficiency.

• Solar Energy
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• v.20 no.1
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• pp.11-20
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• 2000

To get more insight into the buffering effects of the p-${\mu}c$-Si:H Inserted at the p-a-SiC:H/i-a-Si:H interface, we present a systematic numerical simulation using Gummel-Schafetter method. The reduced recombination loss at the p/i interface due to a constant bandgap buffer is analysed in terms of the variation of the p/i Interface region with a short lifetime and the characterisitics of the buffer such as mobility bandgap, acceptor concentration, and D-state density. The numerical modeling on the constant bandgap buffer demonstrates clearly that the buffering effects of the thin p-${\mu}c$-Si:H originate from the shrinkage of highly defective region with a short lifetime in the vicinity of the p/i interface.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.114.2-114.2
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• 2011

비정질 실리콘 박막 태양전지연구에 일반적으로 사용되고 있는 ASA (Advanced Semicon ductor Analysis) simulation을 이용하여 TCO/p에 삽입될 버퍼층의 최적 구조를 설계해보았다. 기본적인 p,i,n층 단일막 data 값을 고정시켜 버퍼층의 광학적 밴드갭을 1.75~1.95eV, 활성화 에너지를 0.3~0.4eV, 두께를 5~15nm로 가변해 보았다. 첫 번째로 동일한 활성화 에너지를 갖는 버퍼층의 광학적 밴드갭을 증가 시켰을 경우 built-in potential이 증가하였으며 이는 개방전압의 증가로 이어졌다. 두 번째로 활성화 에너지가 작은 경우 큰 경우에 비하여 Conduction-band와 Fermi-level의 차이가 증가 하게 되어 활성화 에너지가 큰 경우에 비해 높은 built-in potential을 얻을 수 있었다. 또한 버퍼층과 p층의 접합부분에서의 barrier가 활성화 에너지의 차이를 줄일수록 감소 함 을 알 수 있었다. 장벽의 감소로 정공의 흐름을 방해하는 요소가 줄어들었고 효율도 증가하였다. 마지막으로 버퍼층 두께가 두꺼워 질수록 박막 내에서 빛 흡수가 많아지게 되어 광 흡수층으로 가야할 빛의 양이 줄어들게 되어 단락전류값이 감소하는 것을 알 수 있었다. Simulation결과 버퍼층의 광학적 밴드갭이 1.95eV로 크고 활성화 에너지가 0.3eV이하로 p층에 비하여 낮으며 두께가 5nm로 얇을수록 좋다는 결과를 알 수 있었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.115-118
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• 2017

Highly photosensitive and wide bandgap amorphous silicon oxide (a-$SiO_x$:H) films were developed at low temperature ranges ($100{\sim}150^{\circ}C$) with employing plasma-enhanced chemical vapor deposition by optimizing $H_2/SiH_4$ gas ratio and $CO_2$ flow. Photosensitivity more than $10^5$ and wide bandgap (1.81~1.85 eV) properties were used for making the a-$SiO_x$:H thin film solar cells, which exhibited a high open circuit voltage of 0.987 V at the substrate temperature of $100^{\circ}C$. In addition, a power conversion efficiency of 6.87% for the cell could be improved up to 7.77% by employing a new n-type nc-$SiO_x$:H/ZnO:Al/Ag triple back-reflector that offers better short circuit currents in the thin film photovoltaic devices.