Teflon Sheet as a Large‐Area Gas Seal for Gas Flow Radioactivity Counters

1958 ◽  
Vol 29 (6) ◽  
pp. 536-537
Author(s):  
K. A. Bargh
Keyword(s):  
Gas Flow ◽  
Large Area ◽  
Teflon Sheet

Improved and Large Area Single-Walled Carbon Nanotube Forest Growth by Controlling the Gas Flow Direction

ACS Nano ◽  
2009 ◽  
Vol 3 (12) ◽  
pp. 4164-4170 ◽  
Author(s):  
Satoshi Yasuda ◽  
Don N. Futaba ◽  
Takeo Yamada ◽  
Junichi Satou ◽  
Akiyoshi Shibuya ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Flow ◽  
Flow Direction ◽  
Forest Growth ◽  
Large Area ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon

Optimization of gas flow and etch depth uniformity for plasma etching of large area GaAs wafers

2002 ◽  
Vol 46 (5) ◽  
pp. 685-688 ◽  
Author(s):  
J.W. Lee ◽  
P.G. Jung ◽  
M. Devre ◽  
R. Westermann ◽  
S.J. Pearton
Keyword(s):  
Plasma Etching ◽  
Gas Flow ◽  
Etch Depth ◽  
Large Area

11.0% Stable Efficiency on Large Area, Encapsulated a-Si:H and a-SiGe:H based Multijunction Solar Cells Using HF Technology

2011 ◽  
Vol 1321 ◽  
Author(s):  
A. Banerjee ◽  
D. Beglau ◽  
T. Su ◽  
G. Pietka ◽  
G. Yue ◽  
...  
Keyword(s):  
Solar Cells ◽  
Triple Junction ◽  
Gas Flow ◽  
High Efficiency ◽  
Open Circuit ◽  
Large Area ◽  
Multijunction Solar Cells ◽  
Double Junction ◽  
Junction Structure ◽  
Cell Thickness

ABSTRACTWe report on the investigation of large area a-Si:H/a-SiGe:H double-junction and a-Si:H/a-SiGe:H/a-SiGe:H triple-junction solar cells prepared by our proprietary High Frequency (HF) glow discharge technique. For investigative purposes, we initially used the simpler double-junction structure. We studied the effect of: (1) Ge content, (2) cell thickness, and (3) SiH4 and GeH4 gas flow on the light-induced degradation of the solar cells. Our results show that the double-junction cells with different Ge concentration have open-circuit voltage (Voc) in the range of 1.62-1.75 V. Voc exhibits a flat plateau in the range of 1.65-1.72 V for both initial and stabilized states. The light-induced degradation for cells in this range of Voc is insensitive to the Ge content. In terms of thickness dependence of the intrinsic layers, we found that the initial efficiency increases with cell thickness in the thickness range 2000-4000 Å. However, light-induced degradation increases with increasing thickness. Consequently, the stabilized efficiency is invariant with cell thickness in the thickness range studied. The results of SiH4 and GeH4 gas flow on cell characteristics demonstrate that the deposition rate decreases by only 20% when the active gas flow is reduced to 0.25 times standard flow. The initial and stabilized efficiencies are similar. The information gleaned from the study was used to fabricate high efficiency, large area (~464 cm2) double- and triple-junction solar cells. The highest stable efficiency, as measured by NREL, was 9.8% and 11.0% for the double- and triple-junction structures, respectively.

Design and Characteristics of a Novel Close-Spaced Reactor for Organometallic Epitaxy

1990 ◽  
Vol 204 ◽  
Author(s):  
P.B. Chinoy ◽  
S.K. Ghandhi
Keyword(s):  
Gas Flow ◽  
Deposition Efficiency ◽  
Organometallic Vapor Phase Epitaxy ◽  
Operating Characteristics ◽  
Stagnation Flow ◽  
Large Area ◽  
Flow Rates ◽  
Acceptable Quality ◽  
Nozzle Temperature ◽  
Reactor Pressure

ABSTRACTA novel, close-spaced, inverted, stagnation flow, organometallic vapor phase epitaxy (OMVPE) reactor has been designed and fabricated for achieving high deposition efficiency and good large-area uniformity for solar cell applications. A computer model for this reactor, which is based on the conservation of mass, momentum, energy and species equations, has been used for predicting its operating characteristics. Due to the close spacing between the nozzle and susceptor, extensive measurements of the nozzle temperature were carried out for different reactor conditions and compared with simulation results. The maximum nozzle temperature was about 110°C showing the feasibility of GaAs growth from trimethylgallium and arsine. GaAs epitaxial layers were grown at different susceptor-nozzle distances, gas flow rates, reactor pressures and susceptor temperatures. The morphology, electrical properties and thickness uniformity of the layers were found to be of an acceptable quality. The measured and computed deposition efficiencies were found to be independent of reactor pressure and increasing with decreasing gas flow rates. The highest gallium deposition efficiency achieved was about 42%.

scholarly journals CVD Synthesis of Intermediate State-Free, Large-Area and Continuous MoS2 via Single-Step Vapor-Phase Sulfurization of MoO2 Precursor

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2642
Author(s):  
Tinna Chiawchan ◽  
Harihara Ramamoorthy ◽  
Kanokwan Buapan ◽  
Ratchanok Somphonsane
Keyword(s):  
Vapor Phase ◽  
Intermediate State ◽  
Gas Flow ◽  
Molybdenum Trioxide ◽  
Detailed Examination ◽  
Single Step ◽  
Stoichiometric Ratio ◽  
Large Area ◽  
Wide Range ◽  
Experimental Findings

The low evaporation temperature and carcinogen classification of commonly used molybdenum trioxide (MoO3) precursor render it unsuitable for the safe and practical synthesis of molybdenum disulfide (MoS2). Furthermore, as evidenced by several experimental findings, the associated reaction constitutes a multistep process prone to the formation of uncontrolled amounts of intermediate MoS2−yOy phase mixed with the MoS2 crystals. Here, molybdenum dioxide (MoO2), a chemically more stable and safer oxide than MoO3, was utilized to successfully grow cm-scale continuous films of monolayer MoS2. A high-resolution optical image stitching approach and Raman line mapping were used to confirm the composition and homogeneity of the material grown across the substrate. A detailed examination of the surface morphology of the continuous film revealed that, as the gas flow rate increased by an order of magnitude, the grain-boundary separation dramatically reduced, implying a transition from a kinetically to thermodynamically controlled growth. Importantly, the single-step vapor-phase sulfurization (VPS) reaction of MoO2 was shown to suppress intermediate state formations for a wide range of experimental parameters investigated and is completely absent, provided that the global S:Mo loading ratio is set higher than the stoichiometric ratio of 3:1 required by the VPS reaction.

Microwave PECVD of Micro-Crystalline Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
Wim Soppe ◽  
Camile Devilee ◽  
Sacha Schiermeier ◽  
Harry Donker ◽  
J.K. Rath
Keyword(s):  
Large Scale ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Crystalline Silicon ◽  
Plasma Source ◽  
Growth Conditions ◽  
Scale Production ◽  
Large Area ◽  
Deposition Rates ◽  
Microwave Source

AbstractThe deposition of micro-crystalline silicon by means of PECVD with a new linear microwave plasma source is investigated. This plasma source has successfully been introduced in the large scale production of multi-crystalline Si solar cells for the deposition of passivating silicon nitride layers. Advantages of this linear plasma source are the high deposition rates and the large area (up to 80 cm width, no length limitations) on which a homogeneous deposition can be achieved. Since this source has not been applied for deposition of micro-crystalline silicon before, we explored a large parameter space (substrate temperature, pressure, MW-power, gas flow rates), in order to find optimum growth conditions. It is observed that with this microwave source it is possible to grow micro-crystalline layers at significantly higher silane/hydrogen ratios and higher deposition rates than for conventional RF PECVD. In this paper, structural properties of the silicon layers, as investigated by Raman and FTIR spectroscopy, XRD and SEM measurements are discussed.

The Slope Etching of a-Si:H Film using CF4 + O2 Gas

1991 ◽  
Vol 219 ◽  
Author(s):  
Kang Hyun Sung ◽  
B. W. Park ◽  
J. J. Kim ◽  
C. Y. Kim ◽  
J. I. Choi ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Flow Rate ◽  
Gas Flow ◽  
Silicon Film ◽  
Slope Angle ◽  
Image Sensor ◽  
Treatment Temperature ◽  
Gas Flow Rate ◽  
Large Area ◽  
Thermal Treatment Temperature

ABSTRACTThe slope etching technology of hydrogenated amorphous silicon film (a-Si:H) has been very useful for its devices; thin film transistor, contact image sensor and other large area electronic components. To obtain a good step coverage slope etching was performed by RIE using CF4 gas and optimum amount of O2 gas after modification of photoresist(PR) patterns by thermal treatment. In this experiment, primary factors were1) thermal treatment temperature and time of PR.2) CF4 gas flow rate, etch rate of a-Si:H film and ash rate of PR in proportion to O2 gas flow rate.As a result, the slope angle of 11° was obtained when CF4 gas flow rate was 46 SCCM, O2 gas flow rate was 7 SCCM and thermal treatment temperature and time was 140°C and 30 minutes respectively.

scholarly journals Performance study of large-area glass resistive plate chambers with different spacer configurations

2021 ◽  
Vol 16 (12) ◽  
pp. P12022
Author(s):  
L. Mao ◽  
F. Lagarde ◽  
J. Guo ◽  
X. Wang ◽  
J. Li ◽  
...  
Keyword(s):  
Gas Flow ◽  
Simulation Studies ◽  
Performance Study ◽  
Large Area ◽  
Original Design ◽  
Low Efficiency ◽  
Gas Chamber ◽  
Similar Deformation ◽  
Gas Flow Velocity ◽  
Muon Detection

Abstract Optimization of spacer and gas distribution inside the glass resistive plate chamber (RPC) is reported. Simulation studies demonstrate improvements on the gas flow velocity homogeneity and lower vorticity inside the gas chamber. The optimized spacer configuration (76 spacers) decreases the number of spacers by 24% compared to the original design (100 spacers), thus helps significantly reduce the non-active or low-efficiency area caused by spacers while maintaining similar deformation uniformity of the electrodes. Large area glass RPCs with 1×1 m^2 size using two types of spacer configurations are constructed and tested with cosmic muons events. The muon detection efficiencies for RPCs are greater than 95%.

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