scholarly journals Optimization ofμc-Si1−xGex:H Single-Junction Solar Cells with Enhanced Spectral Response and Improved Film Quality

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Yen-Tang Huang ◽  
Pei-Ling Chen ◽  
Po-Wei Chen ◽  
Hung-Jung Hsu ◽  
Cheng-Hang Hsu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Rf Power ◽  
Single Junction ◽  
Long Wavelength ◽  
Tandem Cell ◽  
Cell Efficiency ◽  
Photo Conductivity ◽  
Gas Ratio ◽  
Incorporation Efficiency

Effects of RF power on optical, electrical, and structural properties ofμc-Si1−xGex:H films was reported. Raman and FTIR spectra fromμc-Si1−xGex:H films reflected the variation in microstructure and bonding configuration. Unlike increasing the germane concentration for Ge incorporation, low RF power enhanced Ge incorporation efficiency inμc-Si1−xGex:H alloy. By decreasing RF power from 100 to 50 W at a fixed reactant gas ratio, the optical bandgap ofμc-Si1−xGex:H was reduced owing to the increase in Ge content from 11.2 to 23.8 at.%, while Ge-related defects and amorphous phase were increased. Consequently, photo conductivity of 1.62 × 10−5 S/cm was obtained for theμc-Si1−xGex:H film deposited at 60 W. By applying 0.9 μm thickμc-Si1−xGex:H absorber withXCof 48% and [Ge] of 16.4 at.% in the single-junction cell, efficiency of 6.18% was obtained. The long-wavelength response ofμc-Si1−xGex:H cell was significantly enhanced compared with theμc-Si:H cell. In the case of tandem cells, 0.24 μm a-Si:H/0.9 μmμc-Si1−xGex:H tandem cell exhibited a comparable spectral response as 0.24 μm a-Si:H/1.4 μmμc-Si:H tandem cell and achieved an efficiency of 9.44%.

Evaluation of Ar-Diluted Silane PECVD for Thin Film Si:H Based Solar Cells

2004 ◽  
Vol 808 ◽  
Author(s):  
J. A. Anna Selvan ◽  
Yuan-Min Li ◽  
Liwei Li ◽  
Alan E. Delahoy
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Nanocrystalline Silicon ◽  
Thin Layers ◽  
Dilution Method ◽  
Critical Question ◽  
Long Wavelength ◽  
Hydrogen Dilution ◽  
Porous Microstructure ◽  
The Stability

ABSTRACTDilution by Ar of silane plasma has been reported to increase the stability of a-Si:H films. A critical question is whether Ar diluted i-layers offer higher stabilized solar cell efficiencies than the conventional hydrogen dilution method. We have fabricated a-Si:H p-i-n solar cells with RF-PECVD i-layers by Ar dilution of silane. Ar dilution ratio (ADR, Ar/SiH4), RF power,pressure, and i-layer thickness were varied. At low ADR < 20, such solar cells show comparable initial efficiencies and stability as those devices having H2-diluted i-layers of similar thickness. For cells made with ADR > 20, the initial efficiency decreases dramatically with further increase in Ar dilution, and light soaking causes only mild changes in efficiencies. The stabilized efficiencies of cells made with high ADR are inferior to the cells produced with low ADR or cells prepared by H2 dilution. Further, Voc of solar cells made with high ADR (> 50) decreases substantially in ambient, indicating a porous microstructure susceptible to oxidation. While thermal annealing improves the Voc, a full recovery of Voc is made by accelerated light soaking.The combination of high power and high ADR can lead to nanocrystalline silicon (nc-Si:H) growth, although nucleation is much more difficult to attain by the Ar dilution method compared to hydrogen dilution. We have succeeded in fabricating p-i-n solar cells with nc-Si:H i-layers prepared by the Ar dilution approach. The double dilution by Ar and hydrogen of silane (Ar+H2+SiH4) can result in nc-Si:H i-layers with enhanced long wavelength spectral response compared to devices incorporating nc-Si:H i-layers grown by H2 dilution only. The nc-Si:H solar cells with Ar+H2 diluted i-layers exhibit no light-induced degradation.Using energetic Ar-rich plasma, in a process much simpler than the traditional nc-Si:H technique, doped a-Si:H thin layers can be prepared to form excellent tunnel junctions for multi-junction solar cells. We demonstrate such a novel, non-contaminating tunnel junction in tandem a-Si/a-Si and a-Si/nc-Si solar cells entirely fabricated in a single-chamber RF-PECVD system.

scholarly journals Wide-Range Enhancement of Spectral Response by Highly Conductive and Transparentμc-SiOx:H Doped Layers inμc-Si:H and a-Si:H/μc-Si:H Thin-Film Solar Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Pei-Ling Chen ◽  
Po-Wei Chen ◽  
Min-Wen Hsiao ◽  
Cheng-Hang Hsu ◽  
Chuang-Chuang Tsai
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Spectral Response ◽  
Wavelength Region ◽  
Thin Film Solar Cells ◽  
Window Layer ◽  
Efficiency Gain ◽  
Silicon Thin Film ◽  
Single Junction ◽  
Wide Range

The enhancement of optical absorption of silicon thin-film solar cells by the p- and n-typeμc-SiOx:H as doped and functional layers was presented. The effects of deposition conditions and oxygen content on optical, electrical, and structural properties ofμc-SiOx:H films were also discussed. Regarding the dopedμc-SiOx:H films, the wide optical band gap (E04) of 2.33 eV while maintaining a high conductivity of 0.2 S/cm could be obtained with oxygen incorporation of 20 at.%. Compared to the conventionalμc-Si:H(p) as window layer inμc-Si:H single-junction solar cells, the application ofμc-SiOx:H(p) increased theVOCand led to a significant enhancement in the short-wavelength spectral response. Meanwhile, the employment ofμc-SiOx:H(n) instead of conventional ITO as back reflecting layer (BRL) enhanced the external quantum efficiency (EQE) ofμc-Si:H single-junction cell in the long-wavelength region, leading to a relative efficiency gain of 10%. Compared to the reference cell, the optimized a-Si:H/μc-Si:H tandem cell by applying p- and n-typeμc-SiOx:H films achieved aVOCof 1.37 V,JSCof 10.55 mA/cm2, FF of 73.67%, and efficiency of 10.51%, which was a relative enhancement of 16%.

Development of a-SiOx:H/a-Si1-xGex:H Tandem Solar Cell for Triple-Junction Solar Cell Applications

2012 ◽  
Vol 1426 ◽  
pp. 125-130
Author(s):  
Y.W. Tseng ◽  
Y.H. Lin ◽  
H.J. Hsu ◽  
C.H. Hsu ◽  
C.C. Tsai
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Silicon Oxide ◽  
Defect Density ◽  
Tandem Solar Cell ◽  
Tandem Solar Cells ◽  
Single Junction ◽  
Cell Efficiency ◽  
Photo Response ◽  
Hydrogenated Amorphous

ABSTRACTIn this work, the development of hydrogenated amorphous silicon oxide (a-SiOx:H) absorber, a-SiOx:H single-junction solar cells and a-SiOx:H/a-Si1-xGex:H tandem solar cells were presented. The oxygen content of the a-SiOx:H materials controlled by changing CO2-to-SiH4 flow ratio had significant influence on its opto-electrical property. As CO2/SiH4 increased from 0 to 2, the bandgap increased from 1.75 to 2.13 eV while the photo-conductivity decreased from 8.25×10-6 to 1.02×10-8 S/cm. Photo-response of over 105 can be obtained as the bandgap was approximately 1.90 eV. The performance of single-junction solar cells revealed a better efficiency can be obtained as the absorber bandgap was in the range of 1.83 to 1.90 eV. Further increase of the absorber bandgap may lead to the increase in bulk defect density which deteriorated the cell efficiency. Finally, a-SiOx:H/a-Si1-xGex:H tandem solar cell was fabricated with the absorber bandgap of 1.90 eV in the top cell. By matching the current between the component cells, the tandem cell efficiency of 7.38% has been achieved.

scholarly journals Development of Hydrogenated Microcrystalline Silicon-Germanium Alloys for Improving Long-Wavelength Absorption in Si-Based Thin-Film Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yen-Tang Huang ◽  
Hung-Jung Hsu ◽  
Shin-Wei Liang ◽  
Cheng-Hang Hsu ◽  
Chuang-Chuang Tsai
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Silicon Germanium ◽  
Volume Fraction ◽  
Thin Film Solar Cells ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Single Junction ◽  
Long Wavelength ◽  
Wavelength Absorption

Hydrogenated microcrystalline silicon-germanium (μc-Si1-xGex:H) alloys were developed for application in Si-based thin-film solar cells. The effects of thegermane concentration(RGeH4)and thehydrogen ratio(RH2)on theμc-Si1-xGex:H alloys and the corresponding single-junction thin-film solar cells were studied. The behaviors of Ge incorporation in a-Si1-xGex:H andμc-Si1-xGex:H were also compared. Similar to a-Si1-xGex:H, the preferential Ge incorporation was observed inμc-Si1-xGex:H. Moreover, a higherRH2significantly promoted Ge incorporation for a-Si1-xGex:H, while the Ge content was not affected byRH2inμc-Si1-xGex:H growth. Furthermore, to eliminate the crystallization effect, the 0.9 μm thick absorbers with a similar crystalline volume fraction were applied. With the increasingRGeH4, the accompanied increase in Ge content ofμc-Si1-xGex:H narrowed the bandgap and markedly enhanced the long-wavelength absorption. However, the bias-dependent EQE measurement revealed that too much Ge incorporation in absorber deteriorated carrier collection and cell performance. With the optimization ofRH2andRGeH4, the single-junctionμc-Si1-xGex:H cell achieved an efficiency of 5.48%, corresponding to the crystalline volume fraction of 50.5% and Ge content of 13.2 at.%. Compared toμc-Si:H cell, the external quantum efficiency at 800 nm had a relative increase by 33.1%.

Investigation of Textured Back Reflectors for Microcrystalline Silicon Based Solar Cells

1999 ◽  
Vol 557 ◽  
Author(s):  
O. Kluth ◽  
O. Vetterl ◽  
R. Carius ◽  
F. Finger ◽  
S. Wieder ◽  
...  
Keyword(s):  
Solar Cells ◽  
Near Infrared ◽  
Spectral Response ◽  
Short Circuit ◽  
Chemical Vapour ◽  
Root Mean Square Roughness ◽  
Microcrystalline Silicon ◽  
Feature Size ◽  
Long Wavelength ◽  
Back Reflectors

AbstractMicrocrystalline silicon (μc-Si:H) solar cells require an effective light trapping in the near infrared (NIR) to enhance the long wavelength spectral response. For this purpose we investigated back reflectors based on texture-etched ZnO/Ag stacks prepared on glass substrates by magnetron sputtering. With decreasing sputter pressure the resulting surface texture of the glass/Ag/ZnO substrates after etching exhibits a larger feature size and root mean square roughness. The increase in feature size corresponds to an increase of diffuse reflectivity. Applied in microcrystalline solar cells prepared by VHF plasma enhanced chemical vapour deposition (PECVD), the reflectors showing the largest feature size (prepared at the lowest possible sputter pressure) yielded the highest long wavelength spectral response. The μc-Si n-i-p cells prepared on the latter back reflector exhibited efficiencies of 6.9 % (short circuit current density jsc= 18.8 mA/cm2) and 7.5 % (jsc=25 mA/cm2) for an i-layer thickness of 1 μm and 3.5 μm, respectively.

Preparation of Narrow-gap a-Si:H Solar Cells by VHF-PECVD Technique

2010 ◽  
Vol 1245 ◽  
Author(s):  
Do Yun Kim ◽  
Ihsanul Afdi Yunaz ◽  
Shunsuke Kasashima ◽  
Shinsuke Miyajima ◽  
Makoto Konagai
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Hydrogen Flow ◽  
Long Wavelength

AbstractOptical, electrical and structural properties of silicon films depending on hydrogen flow rate (RH), substrate temperature (TS), and deposition pressure (PD) were investigated. By decreasing RH and increasing TS and PD, the optical band gap (Eopt) of silicon thin films drastically declined from 1.8 to 1.63 eV without a big deterioration in electrical properties. We employed all the investigated Si thin films for p-i-n structured solar cells as absorbers with i-layer thickness of 300 nm. From the measurement of solar cell performances, it was clearly observed that spectral response in long wavelength was enhanced as Eopt of absorber layers decreased. Using the solar cell whose Eopt of i-layer was 1.65 eV, the highest QE at long wavelength with the short circuit current density (Jsc) of 16.34 mA/cm2 was achieved, and open circuit voltage (Voc), fill factor (FF), and conversion efficiency (η) were 0.66 V, 0.57, and 6.13%, respectively.

Improvement in the spectral response at long wavelength of a-SiGe:H solar cells by exponential band gap design of the i-layer

2002 ◽  
Vol 299-302 ◽  
pp. 1131-1135 ◽  
Author(s):  
R Jimenez Zambrano ◽  
F.A Rubinelli ◽  
J.K Rath ◽  
R.E.I Schropp
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Spectral Response ◽  
Long Wavelength

scholarly journals N-I-P Micromorph Solar Cells on Aluminium Substrates

1996 ◽  
Vol 452 ◽  
Author(s):  
M. Goetz ◽  
P. Torres ◽  
P. Pernet ◽  
J. Meier ◽  
D. Fischer ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
Spectral Response ◽  
Single Layer ◽  
Antireflection Coating ◽  
Microcrystalline Silicon ◽  
Single Junction ◽  
Junction Solar Cell ◽  
Single Junction Solar Cell

AbstractThe first successful deposition of ‘micromorph’ silicon tandem solar cells of the n-i-p-n-i-p configuration is reported. In order to implement the ‘micromorph’ solar cell concept, four key elements had to be prepared: First, the deposition of mid-gap, intrinsic microcrystalline silicon (μc-Si:H) by the 'gas purifier method', second, the amorphous silicon (a-Si:H) n-i-p single junction solar cell, third, the microcrystalline silicon n-i-p single junction solar cell and fourth, the ability of depositing on aluminium sheet substrates.All the solar cells presented have been deposited on flat aluminium sheets, using a single layer antireflection coating to couple the light into the cell. It is shown, that this antireflection concept- together with a flat substrate- holds for amorphous single junction solar cells, but it reaches its limit with the extended range of spectral response of the ‘micromorph’ cell.The best initial efficiencies for each category of n-i-p cells on flat substrates were: 8.7% for the amorphous silicon single junction cell, 4.9% for the microcrystalline silicon single junction cell and 9.25% for the ‘micromorph’ tandem cell.

High Quality Hot-wire Microcrystalline Silicon for Efficient Single and Multijunction N-i-p Solar Cells

2006 ◽  
Vol 910 ◽  
Author(s):  
Robert L. Stolk ◽  
Hongbo Li ◽  
Ronald H. Franken ◽  
Karine H.M. Van der Werf ◽  
Jatindra K. Rath ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Composition ◽  
Chemical Vapor ◽  
Computer Code ◽  
Hot Wire ◽  
Microcrystalline Silicon ◽  
Single Junction ◽  
Tandem Cell ◽  
Bottom Cell ◽  
Current Limiting

AbstractIn this paper, the potential of hot-wire chemical vapor-deposited (HWCVD) microcrystalline silicon (μc-Si) for use in solar cells is explored. Incorporation of the material in the current-limiting bottom cell of two tandem cells on plain stainless steel resulted in FF values as high as 0.77, which is much higher than the highest single junction FF. A combination of experiments, calculations and computer simulations was employed to identify causes for the observed high tandem cell FF values. Both the light intensity and the spectral composition of the bottom cell illumination in a tandem were found to contribute to an increase of the bottom cell FF. The fact that the operational voltage of a tandem cell is higher than that of the current-limiting subcell, was calculated to lead to a tandem FF that can be far higher than that of the limiting cell. Com-puter simulations with the AMPS computer code show that the current mismatch in a tandem cell reduces the recombination in the current-limiting cell, possibly by slightly enhancing the internal field of that cell. Use of a 1.5 μm ìc-Si:H hot-wire deposited absorber layer in a single junction cell on a textured back reflector yielded a Voc, FF and Jsc of 0.543 V, 0.656 and 23.60 mA/cm2, respectively, which combine to an 8.4 % record efficiency for μc-Si single junction n-i-p cells with a hot-wire intrinsic layer.

Effect of Plasma Treatment of the Tco on a-Si Solar Cell Performance

1992 ◽  
Vol 258 ◽  
Author(s):  
F. Demichelis ◽  
R. Galloni ◽  
A. Madan ◽  
C.F. Pirri ◽  
P. Rava ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Hydrogen Plasma ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Solar Cell Performance ◽  
Single Junction ◽  
Plasma Treatments ◽  
Si Solar Cell ◽  
Different Types

ABSTRACTSingle junction a-Si p-i-n solar cells have been deposited by an Ultra High Vacuum (UHV) Multichamber PECVD system reaching an efficiency of 10.1% over 0.1 cm2 and 9.7% over 1 cm2. The effect of hydrogen treatments on the performance of the solar cells was studied on two different types of SnO2 coated substrates and was correlated with the I-V characteristics under AM1.5 (100 mW cm-2) illumination and the spectral response of the devices. The results show that modifications at the TCO/p-layer interface due to the hydrogen plasma treatments are strongly dependent on the initial characteristics of the TCO.

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