• Title/Summary/Keyword: Seeding layer

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Optimization of $p^+$ seeding layer for thin film silicon solar cell by liquid phase epitaxy

  • Lee, Eun-Joo;Lee, Soo-Hong
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.6
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    • pp.260-262
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    • 2005
  • Thickness optimization of heavily doped p-type seeding layer was studied to improve performance of thin film silicon solar cell. We used liquid phase epitaxy (LPE) to grow active layer of $25{\mu}m$ thickness on $p^+$ seeding layer. The cells with $p^+$ seeding layer of $10{\mu}m\;to\;50{\mu}m$ thickness were fabricated. The highest efficiency of a cell is 12.95%, with $V_{oc}=633mV,\;J_{sc}=26.5mA/cm^2$, FF = 77.15%. The $p^+$ seeding layer of the cell is $20{\mu}m$ thick. As thicker seeding layer than $20{\mu}m$, the performance of the cell was degraded. The results demonstrate that the part of the recombination current is due to the heavily doped seeding layer. Thickness of heavily doped p-type seeding layer was optimized to $20{\mu}m$. The performance of solar cell is expected to improve with the incorporation of light trapping as texturing and AR coating.

OPTIMIZATION OF $P^+$ SEEDING LAYER FOR THIN FILM SILICON SOLAR CELL (결정질 실리콘 박막 태양전지의 $P^+$ 씨앗층 형성 최적화에 관한 연구)

  • Lee, Eun-Joo;Lee, Soo-Hong
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.168-171
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    • 2005
  • Thickness optimization of heavily doped p-type seeding layer was studied to improve performance of thin film silicon solar cell. We used liquid phase epitaxy (LPE) to grow active layer of $25{\MU}m$ thickness on p+ seeding layer. The cells with p+ seeding layer of $10{\mu}m\;to\;50{\mu}m$ thickness were fabricated. The highest efficiency of a cell is $12.95\%$, with Voc=633mV, $Jsc=26.5mA/cm^2,\;FF=77.15\%$. The $P^+$ seeding layer of the cell is $20{\mu}m$, thick. As thicker seeding layer than $20{\mu}m$, the performance of the cell was degraded. The results demonstrate that the part of the recombination current is due to the heavily doped seeding layer. Thickness of heavily doped p-type seeding layer was optimized to $20{\mu}m$. The performance of solar cell is expected to improve with the incorporation of light trapping as texturing and AR coating.

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Effects of post-annealing and seeding layers on electrical properties of PLT thin films by MOCVD using ultrasonic spraying (후열처리 및 seeding 층이 초음파분무 MOCVD법에 의한 PLT 박막 제조 시 전기적 특성에 미치는 영향)

  • 이진홍;김기현;박병옥
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.12 no.5
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    • pp.247-252
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    • 2002
  • $(Pb_{1-x}La_x)TiO_3$ (x = 0.1) thin films were prepared on ITO-coated glass substrates by metal organic chemical vapor deposition using ultrasonic spraying. Effects of the post-annealing and the seeding layer on crystallization, microstructures and electrical properties of thin films were investigated. Dielectric constants of films increased due to the modification of crystallization and the changing of a surface morphology by applying the post-annealing. In addition, as the application of PT seed- ing layer offered nucleation sites to PLT thin films, electrical properties of films were enhanced by the increase of crys-tallinity and grain size. The dielectric constant of the films post-heated for 60 min and with a seeding layer was 213 at 1 kHz.

Orientational characteristics of PLT thin films with seeding layer prepared by sol-gel method (Sol-gel법으로 제조한 PLT 박막의 seeding layer 도입에 의한 배향 특성)

  • 김종국;김철기;김재남;박병옥
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.3
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    • pp.468-473
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    • 1998
  • Sol-gel법을 이용하여 PbTiO3에 La을 10mol% 도핑한 박막을 bare Si(100)-wafer 위에 스핀 코팅법을 이용하여 제조하였다. 제조된 박막의 열처리 온도에 따른 결정화 거동을 살펴보고, 씨앗층(seeding layer)을 도입하여 박막의 미세구조 및 배향성을 SEM과 XRD로 관찰하였다. 씨앗층없이 일반적으로 제조된 박막의 경우는 우선 배향성을 나타내지 않았으나, 씨앗층을 도입한 경우에는 씨앗층의 두께 및 열처리 시간에 따라 막의 배향성이 달라졌다.

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Thermodynamics Consideration of Growth Mode of Silver Islands by Transition Metal Seeding (Nb seeding이 Ag 박막 성장모드에 미치는 영향에 대한 열역학적인 고찰)

  • Byon, Eung-Sun;Kim, Dong-Ho;Jeon, Sang-Jo
    • Journal of the Korean institute of surface engineering
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    • v.40 no.1
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    • pp.6-10
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    • 2007
  • For low-emissivity application on window glass, coalescence of thin film silver islands is crucial for high transmittance in the visible and high reflectance in the infrared. It is well known that the underlayer affects the growth mode. In this work, the effect of the underlayer on the growth of silver films deposited by filtered cathodic vacuum arc is discussed. While a nominal 0.1 nm niobium underlayer has promoted the coalescence of silver islands, a 0.2 nm layer did not show these features. From a thermodynamic approach, Nb seeding less one monolayer is considered to reduce the surface energy between the silver atoms and $Nb/TiO_2$ surface, resulting the change of its growth from 3D islands to 2D-layer modes. If the seed layer exceeds one monolayer, however, a rougher surface is formed because the surface energy of Nb itself is superior to that of $Nb-TiO_2$. The onset of silver layer on the roughened Nb surface is required more silver.

The Blanket Deposition and the Sputter Seeding Effects on Substrates of the Chemically Vapor Deposited Cu Films (Sputter Seeding을 이용한 CVD Cu 박막의 비선택적 증착 및 기판의 영향)

  • Park, Jong-Man;Kim, Seok;Choi, Doo-Jin;Ko, Dae-Hong
    • Journal of the Korean Ceramic Society
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    • v.35 no.8
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    • pp.827-835
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    • 1998
  • Blanket Copper films were chemically vapor deposited on six kinds for substrates for scrutinizing the change of characteristics induced by the difference of substrates and seeding layers. Both TiN/Si and {{{{ { SiO}_{2 } }}/Si wafers were used as-recevied and with the Cu-seeding layers of 40${\AA}$ and 160${\AA}$ which were produced by sputtering The CVD processes were exectued at the deposition temperatures between 130$^{\circ}C$ and 260$^{\circ}C$ us-ing (hfc)Cu(VTMS) as a precursor. The deposition rate of 40$^{\circ}C$ Cu-seeded substrates was higher than that of other substrates and especially in seeded {{{{ { SiO}_{2 } }}/Si substrate because of the incubation period reducing in-duced by seeding layer at the same deposition time and temperature. The resistivity of 160${\AA}$ Cu seeded substrate was lower then that of 40 ${\AA}$ because the nucleation and growth behavior in Cu-island is different from the behavior in {{{{ { SiO}_{2 } }} substrate due to the dielectricity of {{{{ { SiO}_{2 } }}.

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Copper Film Growth by Chemical Vapor Deposition: Influence of the Seeding Layer (ICB seeding에 의한 CVD Cu 박막의 증착 및 특성 분석)

  • Yoon, Kyoung-Ryul;Choi, Doo-Jin;Kim, Seok;Kim, Ki-Hwan;Koh, Seok-Keun
    • Korean Journal of Materials Research
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    • v.6 no.7
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    • pp.723-732
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    • 1996
  • Cu films were deposited by chemical wapor deposition on the as-received substrates (TiN/Si) and three kinds of Cu-seeded substrates (Cu/TiN/Si) which had seeding layer in the thick ness of 5 ${\AA}$ and 130 ${\AA}$ coated by ICB(Ionized Cluster Beam) method. The effect of Cu seeding layers on the growth rate, crystallinity, grain size uniformity and film adhesion strength of final CVD-Cu films was investigated by scanning eletron microscopy(SEM), X-ray diffractometry and scratch test. The growth rate was found to incresase somewhat in the case of ICB-seeding. The XRD patterns of the Cu films on the as-received substrate and ICB Cu-seeded substrates exhibited the diffraction peaks corresponding to FCC phase, but the peak intensity ratio($I_{111}/I_{200}$) of Cu films deposited on the ICB Cu-seeded substrates increased compared with that of Cu films on the as-received substrate. The resistivity of final Cu film on 40 ${\AA}$ seeded substrate was observed as the lowest value, 2.42 $\mu\Omega\cdot$cm compared with other Cu films. In adhesion test, as the seeding thickness increased from zero to 130 ${\AA}$, the adhesion strength increased from 21N to 27N.

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Preparation and Gas Permeability of ZIF-7 Membranes Prepared via Two-step Crystallization Technique

  • Li, Fang;Li, Qiming;Bao, Xinxia;Gui, Jianzhou;Yu, Xiaofei
    • Korean Chemical Engineering Research
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    • v.52 no.3
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    • pp.340-346
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    • 2014
  • Continuous and dense ZIF-7 membranes were successfully synthesized on ${\alpha}-Al_2O_3$ porous substrate via two-step crystallization technique. ZIF-7 seeding layer was first deposited on porous ${\alpha}-Al_2O_3$ substrate by in-situ low temperature crystallization, and then ZIF-7 membrane layer can be grown through the secondary high-temperature crystallization. Two synthesis solutions with different concentration were used to prepare ZIF-7 seeding layer and membrane layer on porous ${\alpha}-Al_2O_3$ substrate, respectively. As a result, a continuous and defect-free ZIF-7 membrane layer can be prepared on porous ${\alpha}-Al_2O_3$ substrate, as confirmed by scanning electron microscope. XRD characterization shows that the resulting membrane layer is composed of pure ZIF-7 phase without any impurity. A single gas permeation test of $H_2$, $O_2$, $CH_4$ or $CO_2$ was conducted based on our prepared ZIF-7 membrane. The ZIF-7 membrane exhibited excellent H2 molecular sieving properties due to its suitable pore aperture and defect-free membrane layer.