Film and Solar Cell Properties of a-SiC:H Alloys

1992 ◽  
Vol 258 ◽  
Author(s):  
Yuan-Min Li ◽  
A. Catalano ◽  
B.F. Fieselmann
Keyword(s):  
Open Circuit ◽  
The Novel ◽  
High Hydrogen ◽  
Cell Efficiency ◽  
Hydrogen Dilution ◽  
Silicon Carbon ◽  
Degradation Rates ◽  
Cell Stability ◽  
Hydrogenated Amorphous ◽  
Substrate Temperatures

ABSTRACTHydrogenated amorphous silicon-carbon alloys (a-SiC:H) with 1.9–2.0 eV bandgaps have been grown by glow-discharge using methane as the source of carbon with high hydrogen dilution (CH4+H2) at various substrate temperatures. A thickness dependence of the properties of un-doped films is observed. The photo-electronic properties have been much improved in these undoped alloys compared to those of CH4 based films without H-dilution, however the CH4+H2 based boron doped a-SiC:H films show little improvement. Simple p-i-n single junction solar cells using improved wide-gap a-SiC:H Mayers, based on the CH4+H2 recipe and the novel carbon feedstock trisilylmethane (TSM), show high open circuit voltages and high fill factors. The cell stability under illumination has been tested. There is no correlation in degradation rates between the a-SiC:H cell efficiency and the photoconductivity of the corresponding i-layer films.

Amorphous Silicon-Carbon Alloys for Solar Cells

1993 ◽  
Vol 297 ◽  
Author(s):  
Yuan-Min Li
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
Light Exposure ◽  
Open Circuit ◽  
Hydrogen Dilution ◽  
Silicon Carbon ◽  
Hydrogenated Amorphous ◽  
Substrate Temperatures ◽  
Open Circuit Voltages

Recent efforts to optimize undoped, glow-discharge hydrogenated amorphous silicon-carbon alloys (a-SiC:H) with 1.9-2.0 eV bandgaps for solar cell applications are reviewed. Hydrogen dilution coupled with relatively low substrate temperatures (below 200 °C) have led to great improvements in the optical and phototransport properties of a-SiC:H films. The issue of alternative carbon feedstocks other than methane (CH4) will be explored. The improved a-SiC:H alloys have resulted in solar cells with high open circuit voltages (V∞ > 1.0 volt) and high fill factors (> 0.7). Further, the a-SiC:H solar cell instability upon prolonged light exposure has been much reduced. Correlation will be made between the properties of bulk undoped a-SiC:H films and the performance of p-i-nsingle junction solar cells using corresponding a-SiC:H thin i-layers.

Recombination in n-i-p (Substrate) a-Si:H Solar Cells with Silicon Carbide and Protocrystalline p-Layers

2003 ◽  
Vol 762 ◽  
Author(s):  
V. Vlahos ◽  
J. Deng ◽  
J.M. Pearce ◽  
R.J. Koval ◽  
G.M. Ferreira ◽  
...  
Keyword(s):  
Solar Cells ◽  
Forward Bias ◽  
Open Circuit ◽  
High Hydrogen ◽  
Beneficial Effects ◽  
Hydrogen Dilution ◽  
Cell Structures ◽  
Current Characteristics ◽  
Hydrogenated Amorphous

AbstractA study was carried out on hydrogenated amorphous silicon (a-Si:H) n-i-p (substrate) solar cell structures with p-a-SiC:H and highly diluted p-Si:H layers grown with different dilution ratios R=[H2]/[SiH4]. The contributions of the recombination at the p/i interfaces to the forward bias dark current characteristics were identified and quantified for the different cell structures. In both cell structures the role of the p/i interfaces was identified and it is found that the lowest p/i interface recombination is obtained with protocrystalline p-Si:H layers having no microcrystalline component. The results with p-Si:H layers are attributed not only to their properties but also to the subsurface modification of the intrinsic layer. Evidence is also presented that points to the beneficial effects of the high hydrogen dilution and power used in the deposition of these p-layers in creating the p/i interface regions. The limitations on 1 sun open circuit voltage (VOC) imposed by the p/i recombination present in all the cell structures is consistent with the mechanisms proposed by Deng et al.[1]. The results presented here also point to why the 1 sun VOC in protocrystalline p-Si:H solar cells is higher than that in p-a-SiC:H cells.

Development of Stable a-Si/a-SiGe Tandem Solar Cell Submodules Deposited by a Very High Hydrogen Dilution at Low Temperature

1998 ◽  
Vol 507 ◽  
Author(s):  
Masaki Shima ◽  
Masao Isomura ◽  
Eiji Maruyama ◽  
Shingo Okamoto ◽  
Hisao Haku ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Silicon Germanium ◽  
Structural Variations ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Hydrogen Radicals ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Very High

ABSTRACTThe world's highest stabilized efficiency of 9.5% (light-soaked and measured by the Japan Quality Assurance Organization (JQA)) for an a-Si/a-SiGe superstrate-type solar cell submodule (area: 1200 cm2) has been achieved. This value was obtained by investigating the effects of very-high hydrogen dilution of up to 54:1 (= H2: SiH4) on hydrogenated amorphous silicon germanium (a-SiGe:H) deposition at a low substrate temperature (Ts). It was found that deterioration of the film properties of a-SiGe:H when Ts decreases under low hydrogen dilution conditions can be suppressed by the high hydrogen dilution. This finding probably indicates that the energy provided by hydrogen radicals substitutes for the lost energy caused by the decrease in Ts and that sufficient surface reactions can occur. In addition, results from an estimation of the hydrogen and germanium contents of a-SiGe:H suggest the occurrence of some kinds of structural variations by the high hydrogen dilution. A guideline for optimization of a-SiGe:H films for solar cells can be presented on the basis of the experimental results. The possibility of a-SiGe:H as a narrow gap material for a-Si stacked solar cells in contrast with microcrystalline silicon (μ c-Si:H) will also be discussed from various standpoints. At present, a-SiGe:H is considered to have an advantage over μ1 c-Si:H.

Nanocrystalline Germanium and Germanium Carbide Films and Devices

2005 ◽  
Vol 862 ◽  
Author(s):  
Xuejun Niu ◽  
Jeremy Booher ◽  
Vikram L. Dalal
Keyword(s):  
Grain Size ◽  
Plasma Deposition ◽  
Open Circuit ◽  
Image Sensors ◽  
High Hydrogen ◽  
Strong Function ◽  
Germanium Carbide ◽  
Ecr Plasma ◽  
Hydrogen Dilution ◽  
Steel Substrates

AbstractNanocrystalline Ge and its alloys with C are potentially useful materials for solar cells, thin film transistors and image sensors. In this paper, we discuss the growth and properties of these materials using remote, low pressure ECR plasma deposition. The materials and devices were grown from mixtures of germane, methane and hydrogen. It was found that high hydrogen dilutions (>40:1) were needed to crystallize the films. Studies of x-ray spectra revealed that the grains were primarily <220> oriented. The grain size was a strong function of hydrogen dilution and growth temperature. Higher growth temperatures resulted in larger grain size. High hydrogen dilution tended to reduce grain size. These results can be explained by recognizing that excessive amounts of bonded H can inhibit the growth of <220> grain, which is the thermodynamically favorable direction for grain growth. Grain sizes as large as 80 nm were obtained in nc-Ge. Addition of C reduced the crystallinity. Mobility and carrier concentrations in nc-Ge were measured using Hall effect. Mobility values of ˜5cm2/V-sand carrier concentrations of ˜1x1016/cm3were obtained in larger grains. p+nn+ devices were fabricated on stainless steel substrates and compared with similar devices deposited in nc-Si:H. It was found that the voltage decreased and current increased in nc-Ge devices, in comparison with devices in nc-Si:H. Addition of C to Ge devices increased the open circuit voltage and shifted the quantum efficiency to larger photon energies, as expected.

Reduction of Tail State on Boron Doped Hydrogenated Amorphous Silicon Oxide Films Prepared at High Hydrogen Dilution

2013 ◽  
Vol 13 (12) ◽  
pp. 7826-7833 ◽  
Author(s):  
Jinjoo Park ◽  
S. M. Iftiquar ◽  
Sunwha Lee ◽  
Hyeongsik Park ◽  
Chonghoon Shin ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Silicon Oxide ◽  
Oxide Films ◽  
Hydrogenated Amorphous Silicon ◽  
High Hydrogen ◽  
Tail State ◽  
Hydrogen Dilution ◽  
Boron Doped ◽  
Amorphous Silicon Oxide ◽  
Hydrogenated Amorphous

Properties of a-SiC:H films and solar cells

2000 ◽  
Vol 77 (9) ◽  
pp. 699-704
Author(s):  
R Gharbi ◽  
M Fathallah ◽  
C F Pirri ◽  
E Tresso ◽  
G Crovini ◽  
...  
Keyword(s):  
Solar Cells ◽  
Vapor Deposition ◽  
Open Circuit Voltage ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Light Illumination ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Effect Of Light

a-SiC:H samples and solar cells were made by plasma-enhanced chemical vapor deposition (PECVD) using a multichamber deposition system. The effect of light illumination on samples prepared with and without hydrogen dilution was studied. The phototransport properties of the samples prepared with high hydrogen dilution were more stable versus time of illumination than non diluted ones.The samples were inserted as an intrinsic layer in semitransparent solar cells. The performance of solar cells depends on the energy gap and thickness of the intrinsic layer. High hydrogen dilution may increase the energy gap and act to decrease the structure uniformity. The results show that open circuit voltage Voc decreases with light illumination and depends on the doped p+ layer quality and created defects in the intrinsic layer. PACS Nos.: 70, 72, 40

High hydrogen dilution and low substrate temperature cause columnar growth of hydrogenated amorphous silicon

2010 ◽  
Vol 207 (3) ◽  
pp. 525-529 ◽  
Author(s):  
Paula C. P. Bronsveld ◽  
Tomas Mates ◽  
Antonin Fejfar ◽  
Jan Kočka ◽  
Jatindra K. Rath ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Columnar Growth ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Hydrogenated Amorphous

Effects of high hydrogen dilution at low temperature on the film properties of hydrogenated amorphous silicon germanium

1997 ◽  
Vol 71 (1) ◽  
pp. 84-86 ◽  
Author(s):  
Masaki Shima ◽  
Akira Terakawa ◽  
Masao Isomura ◽  
Makoto Tanaka ◽  
Seiichi Kiyama ◽  
...  
Keyword(s):  
Low Temperature ◽  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Film Properties ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous
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