Amorphous Silicon and Silicon Germanium Alloy Solar Cells Deposited by VHF at High Rates

2001 ◽  
Vol 664 ◽  
Author(s):  
Jeffrey Yang ◽  
Baojie Yan ◽  
Jozef Smeets ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Buffer Layers ◽  
Very High Frequency ◽  
High Quality ◽  
Deposition Rates ◽  
Sige Alloy ◽  
Rf Glow Discharge

ABSTRACTA modified very high frequency (MVHF) glow discharge technique is used to deposit amorphous silicon (a-Si) and amorphous silicon-germanium (a-SiGe) alloy solar cells at high deposition rates. High quality a-Si alloy solar cells have been obtained by using MVHF at deposition rates up to ∼10 Å/s. The cells show good initial and stabilized efficiencies comparable to those obtained from conventional radio-frequency (RF) glow discharge deposition at low rates (∼1 Å/s). However, high quality a-SiGe alloy solar cells are more difficult to achieve at high deposition rates. In this paper, we present the progress made on a-SiGe alloy solar cells by incorporating bandgap profiling and appropriate buffer layers. Using the improved a-SiGe alloy solar cells, a-Si/a-SiGe tandem configurations are made and results presented.

Light-Induced Degradation of Amorphous Silicon-Germanium Alloy Solar Cells Deposited at High Rates

1996 ◽  
Vol 420 ◽  
Author(s):  
S. Sugiyama ◽  
X. Xu ◽  
J. Yang ◽  
S. Guha
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Ion Bombardment ◽  
Ir Absorption ◽  
Film Properties ◽  
Deposition Rates ◽  
Rf Glow Discharge ◽  
Amorphous Silicon Germanium

AbstractWe have studied the light-induced degradation of amorphous silicon-germanium (a-SiGe:H) alloy single-junction solar cells with high initial performance deposited at high rates. The intrinsic layers were deposited using microwave (MW) glow-discharge technique at deposition rates between 10 and 40 Å/s. The results show that light-induced degradation of the cells is higher than that of cells deposited at low rates using RF glow-discharge technique, and it does not strongly depend on deposition rates over this range. The total hydrogen content and the ratio of Si-H2, Ge-H, and Ge-H2 to Si-H bonding estimated by infrared (IR) absorption in films are correlated with the cell degradation results. We have also investigated the effect of ionbombardment on film properties. Films with low ion-bombardment are more porous and have higher composition of Si-H2 and Ge-H2 bonding. Appropriate ion-bombardment makes denser structure in a-SiGe:H alloy films deposited at high rates. This improves the cell performance as well.

Effect of Excitation Frequency on the Performance of Amorphous Silicon Alloy Solar Cells

1998 ◽  
Vol 507 ◽  
Author(s):  
J. Yang ◽  
S. Sugiyama ◽  
S. Guha
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
Excitation Frequency ◽  
Deposition Rates ◽  
Solar Cell Performance ◽  
Single Junction ◽  
Silicon Alloy ◽  
Double Junction ◽  
Junction Structure

ABSTRACTWe have studied amorphous silicon alloy solar cells made by using a modified-very-highfrequency glow discharge at 75 MHz with a deposition rate of ∼6 Å/s. The solar cell performance is compared with those made from conventional glow discharge at 13.56 MHz with lower deposition rates. Cells made at ∼6 Å/s with 75 MHz showed comparable stabilized efficiency to those made at ∼3 Å/s with 13.56 MHz. The best performance, however, was obtained with ∼1 Å/s, including a stabilized 9.3% a-Si alloy single-junction cell employing conventional glow discharge technique. Using 75 MHz, we have achieved 11.1% and 10.0% initial active-area efficiencies for a-Si alloy and a-SiGe alloy n i p cells, respectively. An initial efficiency of 11.0% has also been obtained in a dual bandgap double-junction structure.

Nanostructured Silicon Oxide Dual-Function Layer in Amorphous Silicon Based Solar Cells

2012 ◽  
Vol 1426 ◽  
pp. 69-74 ◽  
Author(s):  
Tining Su ◽  
Baojie Yan ◽  
Laura Sivec ◽  
Guozhen Yue ◽  
Jessica Owens-Mawson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Silicon Oxide ◽  
Cell Structure ◽  
Nanocrystalline Silicon ◽  
Index Of Refraction ◽  
Dual Function ◽  
P Cells

ABSTRACTWe report the results of using n-type hydrogenated nanocrystalline silicon oxide alloy (nc-SiOx:H) in hydrogenated nanocrystalline silicon (nc-Si:H) and amorphous silicon germanium alloy (a-SiGe:H) single-junction solar cells. We used VHF glow discharge to deposit nc-SiOx:H layers on various substrates for material characterizations. We also used VHF glow discharge to deposit the intrinsic layer in nc-Si:H solar cells. RF glow discharge was used for the deposition of the doped layers and the intrinsic layer in a-SiGe:H solar cells. Various substrates such as stainless steel (SS), Ag coated SS, and ZnO/Ag coated SS were used for different cell structures. We found that by using nc-SiOx:H to replace the ZnO and the a-Si:H n-layer in nc-Si:H solar cells, the cell structure is greatly simplified, while the cell performances remain nearly identical to those made using the conventional n-i-p structure on standard ZnO/Ag BR’s. Solar cells with nc-SiOx:H as the n layer directly deposited on textured Ag show similar quantum efficiency (QE) as the n-i-p cells on ZnO/Ag BRs. In both cases, QE is higher than that in the n-i-p cells made directly on Ag coated SS. This effect is probably caused by the shift of surface plasmon-polariton resonance frequency due to the difference in index of refraction of ZnO, nc-SiOx:H, and Si.

High Rate Deposition of Amorphous Silicon Based Solar Cells using Modified Very High Frequency Glow Discharge

2007 ◽  
Vol 989 ◽  
Author(s):  
Guozhen Yue ◽  
Baojie Yan ◽  
Jeffrey Yang ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
High Frequency ◽  
Cell Performance ◽  
High Rate ◽  
Active Area ◽  
Very High Frequency ◽  
Single Junction ◽  
Very High

AbstractWe report our recent progress on high rate deposition of hydrogenated amorphous silicon (a-Si:H) and silicon germanium (a-SiGe:H) based n-i-p solar cells. The intrinsic a-Si:H and a-SiGe:H layers were deposited using modified very high frequency (MVHF) glow discharge. We found that both the initial cell performance and stability of the MVHF a-Si:H single-junction cells are independent of the deposition rate up to 15 Å/s. The average initial and stable active-area cell efficiencies of 10.0% and 8.5%, respectively, were obtained for the cells on textured Ag/ZnO coated stainless steel substrates. a-SiGe:H single-junction cells were also optimized at a rate of ~10 Å/s. The cell performance is similar to those made using conventional radio frequency technique at 3 Å/s. By combining the optimized component cells made at 10 Å/s, an a-Si:H/a-SiGe:H double-junction solar cell with an initial active-area efficiency of 11.7% was achieved.

Hydrogenated Amorphous Silicon Germanium Alloys Prepared by Triode rf Glow Discharge

1986 ◽  
Vol 25 (Part 2, No. 4) ◽  
pp. L276-L278 ◽  
Author(s):  
Takeshige Ichimura ◽  
Takurou Ihara ◽  
Toshio Hama ◽  
Michio Ohsawa ◽  
Hiroshi Sakai ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Rf Glow Discharge ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Silicon Germanium Alloys

scholarly journals High Quality Amorphous Silicon Germanium Alloy Solar Cells Made by Hot-wire CVD at 10 Å/s

2001 ◽  
Vol 664 ◽  
Author(s):  
Qi Wang ◽  
Eugene Iwaniczko ◽  
Jeffrey Yang ◽  
Kenneth Lord ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Chemical Vapor ◽  
Hot Wire ◽  
High Quality ◽  
Area Efficiency ◽  
Back Reflectors ◽  
Double Junction ◽  
Amorphous Silicon Germanium

ABSTRACTHigh quality amorphous silicon germanium (a-SiGe:H) alloys have been obtained using the hot wire chemical vapor deposition (HWCVD) from a gas mixture of SiH4, GeH4, and H2 at a deposition rate of ∼10 Å/s. Solar cells in a SS/n-i-p/ITO configuration are evaluated in which the n- and i-layers are deposited by HWCVD at NREL and the microcrystalline p-layer by conventional RF glow discharge in a separate reactor by United Solar. Effects of hydrogen dilution and step-wise bandgap profile have been studied and optimized. The best cell has an average optical bandgap of 1.6 eV and incorporates multi-bandgap steps where the narrow-most bandgap is near the p-i interface. J-V characteristics are measured under AM 1.5 illumination with a λ>530 nm filter. The best initial power output obtained exceeds 4 mW/cm2, which is usually used as an indicator for a good quality middle-gap cell. Double-junction cells are made on textured Ag/ZnO back reflectors. The bottom cell uses the optimized a-SiGe:H alloy cell by HWCVD, and the top cell uses an optimized a-Si:H cell near the amorphous-to-microcrystalline transition by PECVD at ∼1 Å/s. The best double-junction cell made to date exhibits an initial AM 1.5 active-area efficiency of 11.7%, and a stable efficiency after 1000 hours of one sun light soaking of 9.6%.

Gas Phase Diagnosis of Disilane/Hydrogen RF Glow Discharge Plasma and Its Application to High Rate Growth of High Quality Amorphous Silicon

1999 ◽  
Vol 38 (Part 1, No. 7B) ◽  
pp. 4535-4537 ◽  
Author(s):  
Wataru Futako ◽  
Tomoko Takagi ◽  
Tomonori Nishimoto ◽  
Michio Kondo ◽  
Isamu Shimizu ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Gas Phase ◽  
Discharge Plasma ◽  
High Rate ◽  
Glow Discharge Plasma ◽  
High Quality ◽  
Rf Glow Discharge
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