Thin Film a-Si/poly-Si Multibandgap Tandem Solar Cells With Both Absorber Layers Deposited by Hot Wire Cvd

2001 ◽  
Vol 664 ◽  
Author(s):  
R.E.I. Schropp ◽  
C.H.M. Van Der Werf ◽  
M.K. Van Veen ◽  
P.A.T.T. Van Veenendaal ◽  
R. Jimenez Zambrano ◽  
...  
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Band Gap ◽  
Steel Substrate ◽  
Light Trapping ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Tandem Solar Cells ◽  
Hydrogen Dilution ◽  
P Type

ABSTRACTThe first competitive a-Si/poly-Si multibandgap tandem cells have been made in which the two intrinsic absorber layers are deposited by Hot Wire Chemical Vapor Deposition (HWCVD). These cells consist of two stacked n-i-p type solar cells on a plain stainless steel substrate using plasma deposited n- and p-type doped layers and Hot-Wire deposited intrinsic (i) layers, where the i-layer is either amorphous (band gap 1.8 eV) or polycrystalline (band gap 1.1 eV). In this tandem configuration, all doped layers are microcrystalline and the two intrinsic layers are made by decomposing mixtures of silane and hydrogen at hot filaments in the vicinity of the substrate. For the two layers we used individually optimized parameters, such as gas pressure, hydrogen dilution ratio, substrate temperature, filament temperature, and filament material. The solar cells do not comprise an enhanced back reflector, but feature a natural mechanism for light trapping, due to the texture of the (220) oriented poly-Si absorber layer and the fact that all subsequent layers are deposited conformally. The deposition rate for the throughput limiting step, the poly-Si i-layer, is ≍ 5-6 Å/s. This layer also determines the highest substrate temperature required during the preparation of these tandem cells (500 °C). The initial efficiency obtained for these tandem cells is 8.1 %. The total thickness of the silicon nip/nip structure is only 1.1 µm.

Characterization of Microcrystalline Transition from Amorphous Silicon as a Function of Hydrogen Dilution and Substrate Temperature of Hot-wire CVD

2002 ◽  
Vol 715 ◽  
Author(s):  
Keda Wang ◽  
Haoyue Zhang ◽  
Jian Zhang ◽  
Jessica M. Owens ◽  
Jennifer Weinberg-Wolf ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Sudden Change ◽  
Chemical Vapor ◽  
Threshold Value ◽  
Ir Absorption ◽  
Sudden Increase ◽  
Hot Wire ◽  
Hydrogen Dilution ◽  
Integral Absorption ◽  
Two Peaks

Abstracta-Si:H films were prepared by hot wire chemical vapor deposition. One group was deposited at a substrate temperature of Ts=250°C with varied hydrogen-dilution ratio, 0<R<10; the other group was deposited with fixed R=3 but a varied Ts from 150 to 550°C. IR, Raman and PL spectra were studied. The Raman results indicate that there is a threshold value for the microstructure transition from a- to μc-Si. The threshold is found to be R ≈ 2 at Ts = 250°C and Ts ≈ 200°C at R=3. The IR absorption of Si-H at 640 cm-1 was used to calculate the hydrogen content, CH. CH decreased monotonically when either R or Ts increased. The Si-H stretching mode contains two peaks at 2000 and 2090 cm-1. The ratio of the integral absorption peaks I2090/(I2090+I2090) showed a sudden increase at the threshold of microcrystallinity. At the same threshold, the PL features also indicate a sudden change from a- to μc-Si., i.e. the low energy PL band becomes dominant and the PL total intensity decreases. We attribute the above IR and PL changes to the contribution of microcrystallinity, especially the c-Si gain-boundaries.

DEVELOPMENT OF HIGHLY CONDUCTIVE BORON-DOPED MICROCRYSTALLINE SILICON FILMS FOR APPLICATION IN SOLAR CELLS

2006 ◽  
Vol 20 (03) ◽  
pp. 303-314 ◽  
Author(s):  
QING-SONG LEI ◽  
ZHI-MENG WU ◽  
JIAN-PING XI ◽  
XIN-HUA GENG ◽  
YING ZHAO ◽  
...  
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Boron Doped ◽  
Deposition Processes ◽  
P Type

We have examined the deposition of highly conductive boron-doped microcrystalline silicon (μc- Si:H ) films for application in solar cells. Depositions were conducted in a very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) chamber. In the deposition processes, various substrate temperatures (TS) were applied. Highly conductive p-type microcrystalline silicon films were obtained at substrate temperature lower than 210°C. The factors that affect the conductivity of the films were investigated. Results suggest that the dark conductivity, which was determined by the Hall mobility and carrier concentration, is influenced by the structure. The properties of the films are strongly dependent on the substrate temperature. With TS increasing, the dark conductivity (σd) increases initially; reach the maximum values at certain TS and then decrease. Also, we applied the boron-doped μc- Si:H as p-layers to the solar cells. An efficiency of about 8.5% for a solar cell with μc- Si:H p-layer was obtained.

Development of a hot-wire chemical vapor deposition n-type emitter on p-type crystalline Si-based solar cells

2003 ◽  
Vol 430 (1-2) ◽  
pp. 208-211 ◽  
Author(s):  
Qi Wang ◽  
M.R. Page ◽  
Yueqin Xu ◽  
Eugene Iwaniczko ◽  
Evan Williams ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Hot Wire ◽  
P Type

Properties of High Quality p-Type Micro-Crystalline-Si Prepared by Cat-CVD

2003 ◽  
Vol 762 ◽  
Author(s):  
Hideki Matsumura ◽  
Kouichi Katouno ◽  
Masaya Itoh ◽  
Atsushi Masuda
Keyword(s):  
Solar Cells ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Window Layer ◽  
Hot Wire ◽  
Structural And Optical Properties ◽  
High Quality ◽  
Suitable Material ◽  
Si Solar Cells ◽  
P Type

AbstractProperties of p-type μc-Si prepared by Cat-CVD (Catalytic Chemical Vapor Deposition), often called Hot-Wire CVD, are studied for possible application to window layer of a-Si solar cells. Electrical, structural and optical properties are investigated. It is concluded that Cat-CVD p-type μc-Si is a suitable material as a window layer for Cat-CVD a-Si solar cells.

Hot-wire chemical vapor deposition and characterization of p-type nanocrystalline SiC films and their use in Si heterojunction solar cells

2012 ◽  
Vol 520 (6) ◽  
pp. 2110-2114 ◽  
Author(s):  
Hsin-Yuan Mao ◽  
Dong-Sing Wuu ◽  
Bing-Rui Wu ◽  
Shih-Yung Lo ◽  
Hsin-Yu Hsieh ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Heterojunction Solar Cells ◽  
P Type ◽  
Sic Films

Alternative simple method to realize p-type BaSi2 thin films for Si heterojunction solar cell applications

MRS Advances ◽  
2018 ◽  
Vol 3 (25) ◽  
pp. 1435-1442 ◽  
Author(s):  
Kazuma Takahashi ◽  
Yoshihiko Nakagawa ◽  
Kosuke O. Hara ◽  
Isao Takahashi ◽  
Yasuyoshi Kurokawa ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Substrate Temperature ◽  
Chemical Vapor ◽  
Hole Density ◽  
Simple Method ◽  
Heterojunction Solar Cells ◽  
P Type ◽  
Post Deposition

Abstract:A novel preparation method of B-doped p-type BaSi2 (p-BaSi2) is proposed to realize heterojunction crystalline Si solar cells with p-BaSi2. The method consists of thermal evaporation of BaSi2 on B-doped amorphous Si (a-Si). In this study, the effect of a-Si interlayers and substrate temperature during BaSi2 evaporation on the electrical characteristics and crystalline quality of the evaporated films were investigated. While no cracks were found in the BaSi2 films formed using hydrogenated a-Si deposited by plasma enhanced chemical vapor deposition (PECVD), the films formed with sputtered a-Si have cracks. In addition, BaSi2 films formed with a 600 °C substrate temperature using PECVD a-Si showed p-type characteristics. After a post-deposition anneal at 800 °C for 5 minutes, the film hole density was measured at 1.3×1019 cm-3 and boron was found to be uniformly distributed throughout the film. These results show that the proposed method using PECVD is promising to obtain p-BaSi2 thin films with high hole density for p-BaSi2/n-type crystalline Si heterojunction solar cells.

Materials Optimization for Silicon Heterojunction Solar Cells Using Spectroscopic Ellipsometry

2007 ◽  
Vol 989 ◽  
Author(s):  
Dean Levi ◽  
Eugene Iwanizcko ◽  
Steve Johnston ◽  
Qi Wang ◽  
Howard M Branz
Keyword(s):  
Activation Energy ◽  
Solar Cells ◽  
Substrate Temperature ◽  
Temperature Dependence ◽  
Spectroscopic Ellipsometry ◽  
Surface Passivation ◽  
Light Trapping ◽  
Chemical Vapor ◽  
Thin Layers ◽  
Silicon Substrates

AbstractOur research team has used hot wire chemical vapor deposition (HWCVD) to fabricate silicon heterojunction (SHJ) solar cells on p-type FZ silicon substrates with efficiencies as high as 18.2%. The best cells are deposited on anisotropically-textured (100) silicon substrates where an etching process creates pyramidal facets with (111) crystal faces. Texturing increases Jsc through enhanced light trapping, yet our highest Voc devices are deposited on un-textured (100) substrates. One of the key factors in maximizing the efficiency of our SHJ devices is the process of optimization of the material properties of the 3 - 5 nm thick hydrogenated amorphous silicon (a-Si:H) layers used to create the junction and back contact in these cells. Such optimization is technically challenging because of the difficulty in measuring the properties of extremely thin layers. This difficulty is compounded by the fact that the properties of such amorphous layers are substrate- and thickness-dependent. In this study, we have utilized spectroscopic ellipsometry (SE) and photoconductivity decay to conclude that a-Si:H films grown on (111) substrates are substantially similar to films grown on (100) substrates. In addition, analysis of the substrate temperature dependence of surface roughness evolution reveals a substrate-independent mechanism of surface smoothening with an activation energy of 0.28 eV. Analysis of the substrate temperature dependence of surface passivation reveals a passivation mechanism with an activation energy of 0.63 eV.

Study of CdxZn1-xTe Thin Films with Cu Layers

2013 ◽  
Vol 329 ◽  
pp. 114-117
Author(s):  
Shuo Jin ◽  
Li Li Wu ◽  
Wen Wu Wang ◽  
Guang Gen Zeng ◽  
Liang Huan Feng ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Solar Cells ◽  
Band Gap ◽  
Carrier Density ◽  
Promising Material ◽  
Electrical And Optical Properties ◽  
Tandem Solar Cells ◽  
Conduction Type ◽  
P Type

CdxZn1-xTe is a promising material for tandem solar cells with a continuously adjustable band gap from 1.45eV to 2.26eV, but p-type CdxZn1-xTe with higher carrier density is rarely reported. CdxZn1-xTe thin films with Cu layers were deposited by vacuum co-evaporation in sequence and annealed in low vacuum in this paper. The compositional, structural, morphological, electrical and optical properties were studied. The results show that zinc-blended Cd0.4Zn0.6Te films with (111) preferred orientation were fabricated. Conduction type of annealed CdxZn1-xTe films with Cu layers will change from intrinsic to p-type. Cu doped CdxZn1-xTe thin films with carrier density of 1018~1019cm-3 and the band-gap of 1.89~1.93eV can be obtained. It demonstrates that Cu is an effective p-type dopant for CdxZn1-xTe thin films.

Higher efficiency of n-i-p solar cells by Hot-Wire CVD at moderate temperatures

2001 ◽  
Vol 664 ◽  
Author(s):  
Marieke K. van Veen ◽  
Ruud E.I. Schropp
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Open Circuit Voltage ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Open Circuit ◽  
Hot Wire ◽  
Tandem Solar Cells ◽  
Back Reflectors ◽  
Absorbing Layer

ABSTRACTHot-Wire deposited amorphous silicon is an excellent material for the incorporation as the absorbing layer in n-i-p solar cells. We decreased the deposition temperature from 430 °C to 250 °C, keeping device quality (opto-)electrical properties of the a-Si:H layers. This enables application of Hot-Wire deposited a-Si:H in p-i-n structures and tandem solar cells. Layers deposited at 250 °C have been applied in efficient n-i-p and n-i-p/n-i-p solar cells. The deposition rate of the intrinsic layer was about 10 Å/s. No optical enhancements, like texturing or back reflectors, were used. Single-junction cells with a fill factor of 0.72 and an open-circuit voltage of 0.89 V have been produced. On a flexible stainless steel substrate, an initial efficiency of 7.2 % was recorded. Tandem cells also show a high fill factor (0.71) and open-circuit voltage (1.70 V), resulting in an initial efficiency of 8.5 %.

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