Nano-Crystalline Si Based Alloy (nc-SiXY) with Band Gap of 1.5 eV as the Solar Cell Absorber Layer Fabricated by VHF-PECVD Technique

2012 ◽  
Vol 1426 ◽  
pp. 87-92
Author(s):  
Feng Zhu ◽  
Jian Hu ◽  
Ilvydas Matulionis ◽  
Josh Gallon ◽  
Arun Madan
Keyword(s):  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Optical Bandgap ◽  
Absorber Layer ◽  
Crystalline Volume Fraction ◽  
Very High Frequency ◽  
Nano Crystalline ◽  
Silicon Based ◽  
Gas Ratio

ABSTRACTWe describe the properties of nano-crystalline silicon based alloy (nc-SiXY) prepared by a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) technique with silane (SiH4) and XY gas mixtures and diluted in hydrogen (H2) at low deposition temperature. Varying the gas ratio among SiH4, H2 and XY gasses could alter the optical bandgap and structure. The nc-Si films with high crystalline volume fraction were first prepared, and then the XY gasses were added in order to tune the microstructure and opto-electronic properties of this nano-crystalline silicon based alloy. We have characterized the materials using UV-VIS-NIR, Raman, Constant Photocurrent Method (CPM), dark- and photo-conductivity. As XY gas flows were increased, the optical bandgap of nc-SiXY films increased, while its crystalline volume fraction and conductivity decreased. With proper control of the silane concentration, XY/SiH4 gas ratio, and deposition pressure, we have fabricated the nc-SiXY film with optical bangap of about 1.5eV. Applying this material as the absorber layer in p-i-n devices with configuration of textured ZnO/nc-p+/nc-SiXY/a-n+/Ag, the efficiency is 7.25% (Voc=0.616V, Jsc=17.69mA/cm2, FF= 0.666) with thickness of ∼0.8μm.

scholarly journals Effects of Chamber Pressures on the Passivation Layer of Hydrogenated Nano-Crystalline Silicon Mixed-Phase Thin Film by Using Microwave Annealing

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2199
Author(s):  
Jia-Hao Lin ◽  
Hung-Wei Wu ◽  
Wei-Chen Tien ◽  
Cheng-Yuan Hung ◽  
Shih-Kun Liu
Keyword(s):  
Thin Film ◽  
Carrier Lifetime ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Mixed Phase ◽  
Passivation Layer ◽  
Very High Frequency ◽  
Microwave Annealing ◽  
Symmetric Structure ◽  
Nano Crystalline

This paper proposes the effects of chamber pressures on the passivation layer of hydrogenated nano-crystalline silicon (nc-Si:H) mixed-phase thin film using microwave annealing (MWA) to achieve a high-quality thin film. The use of 40.68 MHz very-high-frequency plasma-enhanced chemical vapor deposition (VHFPECVD) deposited the nc-Si:H mixed-phase thin film on the top and bottom of the n-type crystalline silicon substrate. The chamber pressures (0.2, 0.4, 0.6, and 0.8 Torr) of the VHFPECVD were critical factors in controlling the carrier lifetime of the symmetric structure. By using the VHFPECVD to deposit the nc-Si:H and using the MWA to enhance the quality of the symmetric structure, the deposited nc-Si:H’s properties of a crystalline volume fraction of 29.6%, an optical bandgap of 1.744 eV, and a carrier lifetime of 2942.36 μs were well achieved, and could be valuable in thin-film solar-cell applications.

The dependence of the crystalline volume fraction on the crystallite size for hydrogenated nanocrystalline silicon based solar cells

2013 ◽  
Vol 1536 ◽  
pp. 113-118 ◽  
Author(s):  
K. J. Schmidt ◽  
Y. Lin ◽  
M. Beaudoin ◽  
G. Xia ◽  
S. K. O'Leary ◽  
...  
Keyword(s):  
Solar Cells ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Nanocrystalline Silicon ◽  
Oxygen Impurity ◽  
Crystalline Volume Fraction ◽  
Three Samples ◽  
Crystallite Sizes ◽  
Silicon Based ◽  
The Impact

ABSTRACTWe have performed an analysis on three hydrogenated nanocrystalline silicon (nc-Si:H) based solar cells. In order to determine the impact that impurities play in shaping the material properties, the XRD and Raman spectra corresponding to all three samples were measured. The XRD results, which displayed a number of crystalline silicon-based peaks, were used in order to approximate the mean crystallite sizes through Scherrer's equation. Through a peak decomposition process, the Raman results were used to estimate the corresponding crystalline volume fraction. It was noted that small crystallite sizes appear to favor larger crystalline volume fractions. This dependence seems to be related to the oxygen impurity concentration level within the intrinsic nc-Si:H layers.

Role of deposition pressure on properties of phosphorus doped hydrogenated nano-crystalline silicon (nc-Si:H) thin films prepared by Cat-CVD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Bharat Gabhale ◽  
Ashish Waghmare ◽  
Subhash Pandharkar ◽  
Ajinkya Bhorde ◽  
Shruthi Nair ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
High Deposition Rate ◽  
Deposition Pressure ◽  
Cvd Method ◽  
Nano Crystalline ◽  
Phosphorus Doped

Abstract: Phosphorus doped hydrogenated nano-crystalline silicon (nc-Si:H) thin films were synthesized by catalytic chemical vapor deposition (Cat-CVD) method. The effect of deposition pressure on opto-electronic and structural properties was studied using various analysis techniques such as low angle XRD analysis, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy and dark conductivity etc. From low angle XRD and Raman spectroscopy analysis it is observed that increase in deposition pressure causes Si:H films to transform and transit from amorphous to crystalline phase. At optimized deposition pressure (300 mTorr), phosphorous doped nc-Si:H films having crystallite size of  29 nm and crystalline volume fraction of  58 % along with high deposition rate ( 29.7 Å/s) have been obtained. The band gap was found to be  1.98 eV and hydrogen content was as low as ( 1.72 at. %) for these films. The deposited films can be useful as n-type layer for Si:H based p-i-n, tandem and c-Si hetero-junction solar cells

Properties of Nano-crystalline Silicon-Carbide Films Prepared Using Modulated RF- PECVD

2009 ◽  
Vol 1153 ◽  
Author(s):  
Feng Zhu ◽  
Jian Hu ◽  
Ilvydas Matulionis ◽  
Augusto Kunrath ◽  
Arun Madan
Keyword(s):  
Silicon Carbide ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Dark Conductivity ◽  
Crystalline Volume Fraction ◽  
Photothermal Deflection Spectroscopy ◽  
Nano Crystalline ◽  
Dc Bias ◽  
Photothermal Deflection ◽  
Sic Films

AbstractWe report on the fabrication of nano-crystalline silicon-carbide (nc-SiC) using pulse modulated RF-PECVD technique, from silane (SiH4) and methane (CH4) gas mixtures which is highly diluted in hydrogen (H2). The microstructure of nc-SiC material is nanometer-size silicon crystallites embedded in amorphous silicon-carbide (a-SiC) matrix. As carbon incorporation in nc-Si film increases, the bandgap is enlarged from 1.1eV to 1.55eV as measured by Photothermal Deflection Spectroscopy (PDS) while the crystalline volume fraction decreases from 70% to about 20%. It is found that the crystalline volume fraction, grain size and dark conductivity of nc-SiC films can be enhanced with applying a negative DC bias to substrate during deposition.

Intrinsic and Doped m c-Si:H TFT Layers using 13.56 MHz PECVD at 250°C

2004 ◽  
Vol 808 ◽  
Author(s):  
Czang-Ho Lee ◽  
Denis Striakhilev ◽  
Arokia Nathan
Keyword(s):  
Performance Improvement ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Rf Power ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Low Threshold

ABSTRACTUndoped and n+ hydrogenated microcrystalline silicon (μc-Si:H) films for thin film transistors (TFTs) were deposited at a temperature of 250°C with 99 ∼ 99.6 % hydrogen dilution of silane by standard 13.56 MHz plasma enhanced chemical vapor deposition (PECVD). High crystallinity m c-Si:H films were achieved at 99.6 % hydrogen dilution and at low rf power. An undoped 80 nm thick m c-Si:H film showed a dark conductivity of the order of 10−7 S/cm, the photosensitivity of an order of 102, and a crystalline volume fraction of 80 %. However, a 60 nm thick n+ μc-Si:H film deposited using a seed layer showed a high dark conductivity of 35 S/cm and a crystalline volume fraction of 60 %. Using n+ μc-Si:H films as drain and source contact layers in a-Si:H TFTs provides substantial performance improvement over n+ a-Si:H contacts. Finally, fully μ c-Si:H TFTs incorporating intrinsic m c-Si:H films as channel layers and n+ μc-Si:H films as contact layers have been fabricated and characterized. These TFTs exhibit a low threshold voltage and a field effect mobility of 0.85 cm2/Vs, and are far more stable under gate bias stress than a-Si:H TFTs.

Effect of Hydrogen Radical on Properties of Hydrogen in Hydrogenated Microcrystalline Silicon

2000 ◽  
Vol 609 ◽  
Author(s):  
Takashi Itoh ◽  
Noriyuki Yamana ◽  
Hiroki Inouchi ◽  
Norimitsu Yoshida ◽  
Hidekuni Harada ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Integrated Intensity ◽  
Hydrogen Radical ◽  
Integrated Intensities

ABSTRACTHydrogenated microcrystalline silicon (μc-Si:H) films are prepared by hot-wire assisted plasma enhanced chemical vapor deposition, which controls the hydrogen radical density by filament temperatures, Tf, without changing other conditions. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is studied using infrared absorption and gas effusion spectroscopies. The hydrogen concentration decreases with increasing Tf. The crystalline volume fraction, Xc, increases with Tf and shows a peak at Tf of 1850 °C. Integrated intensities of the modes near 2000 and 2100 cm-1 decrease with increasing Tf. Integrated intensity of the mode near 880 cm-1 shows almost same tendency of Xc. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is discussed.

Electronic Properties of Microcrystalline Silicon

1997 ◽  
Vol 467 ◽  
Author(s):  
R. Carius ◽  
F. Finger ◽  
U. Backhausen ◽  
M. Luysberg ◽  
P. Hapke ◽  
...  
Keyword(s):  
Vapour Deposition ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapour ◽  
Structural Defects ◽  
Photoluminescence Properties ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

ABSTRACTThe electronic and optical properties of microcrys tall ine silicon films prepared by plasma enhanced chemical vapour deposition are investigated with Hall-effect, electrical conductivity, photothermal deflection spectroscopy and photoluminescence measurements. In particular, the influence of the grain size and the crystalline volume fraction on the conductivity, the carrier density and the Hall mobility is investigated in highly doped films. A percolation model is proposed to describe the observed transport data. Photoluminescence properties were studied in un-doped films. It is proposed that the photoluminescence is due to recombination at structural defects similar to those observed in crystalline silicon.

Microstructure and Electric Transport Characteristic of Microcrystalline Silicon Films Fabricated by Very High Frequency Plasma Enhanced Chemical Vapor Deposition

2010 ◽  
Vol 663-665 ◽  
pp. 600-603
Author(s):  
Xiang Wang ◽  
Rui Huang ◽  
Jie Song ◽  
Yan Qing Guo ◽  
Chao Song ◽  
...  
Keyword(s):  
High Frequency ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Hydrogen Flow ◽  
Transmission Electron ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
Very High

Microcrystalline silicon (μc-Si:H) film deposited on silicon oxide in a very high frequency plasma enhanced chemical vapor deposition with highly H2 dilution of SiH4 has been investigated by Raman spectroscopy and high resolution transmission electron microscopy. Raman spectroscopy results show that the crystalline volume fraction increases with increasing the hydrogen flow rate and for the hydrogen flow rate of 160 sccm, the crystalline volume fraction reaches to 67.5%. Nearly parallel columnar structures with complex microstructure are found from cross-sectional transmission electron microscopy images of the film. The temperature depend dark conductivity and activation energy are studied in order to investigate the electronic transport processes in the nc-Si films.

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