High Rates and Very Low Temperature Fabrication of Polycrystalline Silicon From Fluorinated Source GAS and Their Transport Properties

1999 ◽  
Vol 557 ◽  
Author(s):  
T. Kamiya ◽  
K. Nakahata ◽  
K. Ro ◽  
C. M. Fortmann ◽  
I. Shimizu
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Low Temperature ◽  
Polycrystalline Silicon ◽  
Gas Flow ◽  
Open Circuit ◽  
Glow Discharge Plasma ◽  
Very High Frequency ◽  
Crystalline Films ◽  
Gas Flow Ratio

AbstractLow temperature (50-300°C) growth of polycrystalline silicon (poly-Si) by very high frequency (100MHz) glow-discharge plasma enhanced CVD using SiF4 and H2mixtures was studied. The poly-Si microstructure was strongly affected by the SiF4/H2 gas flow ratio. For example, either (220) or (400) preferentially oriented films were prepared by appropriate SiF4/H2 ratio selection. The addition of small SiH4 flows to the SiF4/H2 mixtures could be used to increase the growth rate while the SiF4/H2 continued to control the film structures such as preferential orientation. Highly crystalline films were grown at a growth rate of 0.52nm/s using SiF4/H2/SiH4 flow rates of 30/90/2.Osccm (respectively). However, at higher SiH4 flows amorphous films were deposited. Under the small SiF4/H2 ratio condition, highly crystallized poly-Si was grown at temperatures as low as 50°C. N/i/Pt Schottky diode solar cells were prepared using these poly-Si for both the n- and the i-layers. These solar cells exhibited good performance; for example, open circuit voltages over 0.32V. N-i-p solar cell results are very promising with 6.2% of conversion efficiency being achieved in the initial trials.

Advances in the Characterization of Compositionally-graded Layers in Amorphous Semiconductor Solar Cells by Real Time Spectroellipsometry

1996 ◽  
Vol 420 ◽  
Author(s):  
R. W. Collins ◽  
Sangbo Kim ◽  
Joohyun Koh ◽  
J. S. Burnham ◽  
Lihong Jiao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Real Time ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Interface Layer ◽  
Open Circuit ◽  
Amorphous Semiconductor ◽  
Deposition Parameters ◽  
Gas Flow Ratio ◽  
Graded Layers

AbstractWe have developed a real time spectroellipsometry data analysis procedure that allows us to characterize compositionally- graded amorphous semiconductor alloy thin films prepared by plasma-enhanced chemical vapor deposition (PECVD). As an example, we have applied the analysis to obtain the depth-profile of the optical gap and alloy composition with ≤15 Å resolution for a hydrogenated amorphous silicon-carbon alloy (a-Si1−xCx:H) film prepared by continuously varying the gas flow ratio z=[CH4]/{[CH4]+[SiH4]} in the PECVD process. The graded layer has been incorporated at the p/i interface of widegap a-Si1−xCx:H (x∼0.05) p-i-n solar cells, and consistent improvements in open-circuit voltage have been demonstrated. The importance of the graded-layer characterization is the ability to relate improvements in device performance directly to the physical properties of the interface layer, rather to the deposition parameters with which they were prepared.

scholarly journals GaInP/GaAs/poly-Si Multi-Junction Solar Cells by in Metal Balls Bonding

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 726
Author(s):  
Ray-Hua Horng ◽  
Yu-Cheng Kao ◽  
Apoorva Sood ◽  
Po-Liang Liu ◽  
Wei-Cheng Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Low Temperature ◽  
Triple Junction ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Metal Line ◽  
Solar Simulator ◽  
Junction Solar Cell

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.

Polycrystalline silicon thin-film solar cells prepared by layered laser crystallization with 540mV open circuit voltage

2014 ◽  
Vol 562 ◽  
pp. 430-434 ◽  
Author(s):  
Jonathan Plentz ◽  
Gudrun Andrä ◽  
Annett Gawlik ◽  
Ingmar Höger ◽  
Guobin Jia ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Polycrystalline Silicon ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Thin Film Solar Cells ◽  
Laser Crystallization ◽  
Silicon Thin Film

Protocrystalline Si:H p-type Layers for Maximization of the Open Circuit Voltage in a-Si:H n-i-p Solar Cells

2002 ◽  
Vol 715 ◽  
Author(s):  
R. J. Koval ◽  
Chi Chen ◽  
G. M. Ferreira ◽  
A. S. Ferlauto ◽  
J. M. Pearce ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Film Growth ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Single Step ◽  
Rf Plasma ◽  
Growth Regime

AbstractWe have revisited the issue of p-layer optimization for amorphous silicon (a-Si:H) solar cells, correlating spectroscopic ellipsometry (SE) measurements of the p-layer in the device configuration with light current-voltage (J-V) characteristics of the completed solar cell. Working with p-layer gas mixtures of H2/SiH4/BF3 in rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) for n-i-p solar cells is obtained using p-layers prepared with the maximum possible hydrogen-dilution gas-flow ratio R=[H2]/[SiH4], but without crossing the thickness-dependent transition from the a-Si:H growth regime into the mixed-phase amorphous + microcrystalline [(a+μc)-Si:H] regime for the ∼200 Å p-layers. As a result, optimum single-step p-layers are obtained under conditions similar to those applied for optimum i-layers, i.e., by operating in the so-called “protocrystalline” Si:H film growth regime. The remarkable dependence of the p-layer phase (amorphous vs. microcrystalline) and n-i-p solar cell Voc on the nature of the underlying i-layer surface also supports this conclusion.

Low-Temperature Processed Hybrid Organic/Silicon Solar Cells with Power Conversion Efficiency up to 6.5%

2015 ◽  
Vol 1771 ◽  
pp. 201-206 ◽  
Author(s):  
M. Weingarten ◽  
T. Zweipfennig ◽  
A. Vescan ◽  
H. Kalisch
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Schottky Diode ◽  
Current Density ◽  
Short Circuit ◽  
Power Conversion ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Organic Silicon ◽  
Hybrid Devices

ABSTRACTHybrid organic/silicon heterostructures have become of great interest for photovoltaic application due to their promising features (e.g. easy fabrication in a low-temperature process) for cost-effective photovoltaics. This work is focused on solar cells with a hybrid heterojunction between the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) and n-doped monocrystalline silicon. As semi-transparent top contact, a thin (15 nm) Au layer was employed. Devices with different P3HT thicknesses were processed by spin-casting and compared with a reference Au/n-Si Schottky diode solar cell.The current density-voltage (J-V) measurements of the hybrid devices show a significant increase in open-circuit voltage (VOC) from 0.29 V up to 0.50 V for the best performing hybrid devices compared to the Schottky diode reference, while the short-circuit current density (JSC) does not change significantly. The increased VOC indicates that P3HT effectively reduces the reverse electron current into the gold contact. The wavelength-dependent JSC measurements show a decreased JSC in the wavelength range of P3HT absorption. This is related to the reduced JSC generation in silicon not being compensated by JSC generation in P3HT. It is concluded that the charge generation in P3HT is less efficient than in silicon.After a thermal annealing of the hybrid P3HT/silicon solar cells, we achieved power conversion efficiencies (PCE) (AM1.5 illumination) up to 6.5% with VOC of 0.52 V, JSC of 18.6 mA/cm² and a fill factor (FF) of 67%. This is more than twice the efficiency of the reference Schottky diode.

Effects of low-temperature annealing on polycrystalline silicon for solar cells

2011 ◽  
Vol 95 (2) ◽  
pp. 559-563 ◽  
Author(s):  
Robert Slunjski ◽  
Ivana Capan ◽  
Branko Pivac ◽  
Alessia Le Donne ◽  
Simona Binetti
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Polycrystalline Silicon ◽  
Low Temperature Annealing

Thin-film polycrystalline-silicon solar cells on high-temperature glass based on aluminum-induced crystallization of amorphous silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Dries Van Gestel ◽  
Ivan Gordon ◽  
Lode Carnel ◽  
Linda R. Pinckney ◽  
Alexandre Mayolet ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
High Temperature ◽  
Amorphous Silicon ◽  
Polycrystalline Silicon ◽  
Open Circuit ◽  
Si Solar Cells ◽  
Induced Crystallization ◽  
Seed Layers ◽  
Aluminum Induced Crystallization

AbstractEfficient thin-film polycrystalline-silicon (pc-Si) solar cells on foreign substrates could lower the price of photovoltaic electricity. Aluminum-induced crystallization (AIC) of amorphous silicon followed by epitaxial thickening at high temperatures seems a good way to obtain efficient pc-Si solar cells. Due to its transparency and low cost, glass is well suited as substrate for pc-Si cells. However, most glass substrates do not withstand temperatures around 1000°C that are needed for high-temperature epitaxial growth. In this paper we investigate the use of experimental transparent glass-ceramics with high strain-point temperatures as substrates for pc-Si solar cells. AIC seed layers made on these substrates showed in-plane grain sizes up to 16 μm. Columnar growth was observed on these seed layers during high-temperature epitaxy. First pc-Si solar cells made on glass-ceramic substrates in substrate configuration showed efficiencies up to 4.5%, fill factors up to 75% and open-circuit voltage (Voc) values up to 536 mV. This is the highest Voc reported for pc-Si solar cells on glass and the best cell efficiency reported for cells made by AIC on glass.

High efficiency amorphous and nanocrystalline silicon based multi-junction solar cells deposited at high rates on textured Ag/ZnO back reflectors

2009 ◽  
Vol 1153 ◽  
Author(s):  
Guozhen Yue ◽  
Laura Sivec ◽  
Baojie Yan ◽  
Jeff Yang ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Triple Junction ◽  
High Efficiency ◽  
Nanocrystalline Silicon ◽  
Open Circuit ◽  
Very High Frequency ◽  
Solar Cell Performance ◽  
Single Junction ◽  
Back Reflectors ◽  
Back Reflector

AbstractWe report our recent progress on nc-Si:H single-junction and a-Si:H/nc-Si:H/nc-Si:H triple-junction cells made by a modified very-high-frequency (MVHF) technique at deposition rates of 10-15 Å/s. First, we studied the effect of substrate texture on the nc-Si:H single-junction solar cell performance. We found that nc-Si:H single-junction cells made on bare stainless steel (SS) have a good fill factor (FF) of ˜0.73, while it decreased to ˜0.65 when the cells were deposited on textured Ag/ZnO back reflectors. The open-circuit voltage (Voc) also decreased. We used dark current-voltage (J-V), Raman, and X-ray diffraction (XRD) measurements to characterize the material properties. The dark J-V measurement showed that the reverse saturated current was increased by a factor of ˜30 when a textured Ag/ZnO back reflector was used. Raman results revealed that the nc-Si:H intrinsic layers in the two solar cells have similar crystallinity. However, they showed a different crystallographic orientation as indicated in XRD patterns. The material grown on Ag/ZnO has more random orientation than that on SS. These experimental results suggested that the deterioration of FF in nc-Si:H solar cells on textured Ag/ZnO was caused by poor nc-Si:H quality. Based on this study, we have improved our Ag/ZnO back reflector and the quality of nc-Si:H component cells and achieved an initial and stable active-area efficiencies of 13.4% and 12.1%, respectively, in an a-Si:H/nc-Si:H/nc-Si:H triple-junction cell.

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