Microwave Glow-Discharge Deposition of Amorphous Silicon Based Alloys at High Deposition Rates for Solar Cell Application

1995 ◽  
Vol 377 ◽  
Author(s):  
S. Guha ◽  
X. Xu ◽  
J. Yang ◽  
A. Banerjee
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Growth Conditions ◽  
Deposition Rates ◽  
Solar Cell Application ◽  
Radio Frequency Glow Discharge ◽  
Area Efficiency ◽  
Double Junction ◽  
Silicon Based

ABSTRACTThe optimum deposition conditions for growth of amorphous silicon (a-Si:H) and silicon-germanium (a-SiGe:H) alloys deposited at high rates using microwave glow-discharge are found to be quite different from those for radio-frequency glow-discharge material deposited at low rates. High substrate temperature (350 to 500 °C), low pressure (1–5 mtorr) and positive ion bombardment are found to be desirable for optimum growth conditions at high deposition rates. We have achieved an active-area efficiency of 11.44% for a double-junction structure in which the bottom cell incorporates a-SiGe:H alloy deposited at 100 Å/sec using microwave glow-discharge.

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.

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.

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.

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%.

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.

Hydrogenated amorphous silicon–germanium thin films with a narrow band gap for silicon-based solar cells

2011 ◽  
Vol 11 (1) ◽  
pp. S50-S53 ◽  
Author(s):  
Chao-Chun Wang ◽  
Chueh-Yang Liu ◽  
Shui-Yang Lien ◽  
Ko-Wei Weng ◽  
Jung-Jie Huang ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Band Gap ◽  
Silicon Germanium ◽  
Narrow Band ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Based ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous

Hydrogenated Microcrystalline Silicon Solar Cells Made with Modified Very-High-Frequency Glow Discharge

2002 ◽  
Vol 715 ◽  
Author(s):  
Baojie Yan ◽  
Kenneth Lord ◽  
Jeffrey Yang ◽  
Subhendu Guha ◽  
Jozef Smeets ◽  
...  
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Area Efficiency ◽  
Double Junction ◽  
Stability Data ◽  
The Stability

AbstractHydrogenated microcrystalline silicon (μc-Si:H) solar cells are made using modified veryhigh-frequency (MVHF) glow discharge at deposition rates ∼3-5 Å/s. We find that the solar cells made under certain conditions show degradation in air without intentional light soaking. The short-circuit current drops significantly within a few days after deposition, and then stabilizes. We believe that post-deposition oxygen diffusion along the grain boundaries or cracks is the origin of the ambient degradation. By optimizing the deposition conditions, we have found a plasma regime in which the μc-Si:H solar cells do not show such ambient degradation. The best a-Si:H/μc-Si:H double-junction solar cell has an initial active-area efficiency of 10.9% and is stable against the ambient degradation. The stability data of the solar cells after light soaking are also presented.

Amorphous silicon–germanium for triple and quadruple junction thin-film silicon based solar cells

2015 ◽  
Vol 133 ◽  
pp. 163-169 ◽  
Author(s):  
Jan-Willem Schüttauf ◽  
Bjoern Niesen ◽  
Linus Löfgren ◽  
Maximilien Bonnet-Eymard ◽  
Michael Stuckelberger ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Thin Film Silicon ◽  
Silicon Based ◽  
Amorphous Silicon Germanium

Amorphous Silicon Alloy Solar Cells Near the Threshold of Amorphous-to-Microcrystalline Transition

2000 ◽  
Vol 609 ◽  
Author(s):  
Jeffrey Yang ◽  
Kenneth Lord ◽  
Subhendu Guha ◽  
S.R. Ovshinsky
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Area Efficiency ◽  
Junction Device ◽  
Tandem Structure ◽  
Double Junction ◽  
Junction Structure

ABSTRACTA systematic study has been made of amorphous silicon (a-Si) alloy solar cells using various hydrogen dilutions during the growth of the intrinsic (i) layer. We find that the open-circuit voltage (Voc) of the cells increases as the dilution increases; it then reaches a maximum before it decreases dramatically. This sudden drop in Voc is attributed to the transition from amorphous silicon to microcrystalline inclusions in the i layer. We study i-layer thicknesses ranging from 1000 Å to 5000 Å and find that the transition occurs in all thicknesses investigated. Based on this study, a-Si alloy p i n solar cells suitable for use in the top cell of a high efficiency triple-junction structure are made. By selecting an appropriate dilution, cells with Voc greater than 1 V can be achieved readily. Solar cells made near the threshold not only exhibit higher initial characteristics but also better stability against light soaking. We have compared top cells made near the threshold with our previous best data, and found that both the initial and stable efficiencies are superior for the near-threshold cells. For an a-Si/a-Si double-junction device, a Voc value exceeding 2 V has been obtained using thin component cells. Thicker component cells give rise to an initial active-area efficiency of 11.9% for this tandem structure.

Infrared Spectroscopy of Deuterated a-Si, Ge:D, F Alloys Prepared by DC Glow Discharge Deposition

1986 ◽  
Vol 70 ◽  
Author(s):  
Y. Okada ◽  
D. Slobodin ◽  
S. F. Chou ◽  
R. Schwarz ◽  
S. Wagner
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Glow Discharge ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Dc Glow Discharge ◽  
Thermochemical Equilibrium ◽  
Amorphous Silicon Germanium ◽  
Glow Discharge Deposition

ABSTRACTDeuterated and fluorinated amorphous silicon-germanium alloys, a-Si, Ge:D, F, were studied by Fourier transform infrared (IR) spectroscopy. No Ge.-F modes are observed. The intensity of the Si-F and Si-F2 modes increases with Ge concentration. So does thae intensity of SiF4 which is trapped as isolated molecules. No DF (IR) or F2 (Raman) is observed. The IR spectra of alloys annealed at 300, 400, 500 and 600° C show that the fluorine in the Si-F and Si-F2 groups and in the SiF4 molecules is in thermochemical equilibrium.

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