Hydrogenated Microcrystalline Silicon Solar Cells Made with Modified Very-High-Frequency Glow Discharge

2002 ◽  
Vol 715 ◽  
Author(s):  
Baojie Yan ◽  
Kenneth Lord ◽  
Jeffrey Yang ◽  
Subhendu Guha ◽  
Jozef Smeets ◽  
...  
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Area Efficiency ◽  
Double Junction ◽  
Stability Data ◽  
The Stability

AbstractHydrogenated microcrystalline silicon (μc-Si:H) solar cells are made using modified veryhigh-frequency (MVHF) glow discharge at deposition rates ∼3-5 Å/s. We find that the solar cells made under certain conditions show degradation in air without intentional light soaking. The short-circuit current drops significantly within a few days after deposition, and then stabilizes. We believe that post-deposition oxygen diffusion along the grain boundaries or cracks is the origin of the ambient degradation. By optimizing the deposition conditions, we have found a plasma regime in which the μc-Si:H solar cells do not show such ambient degradation. The best a-Si:H/μc-Si:H double-junction solar cell has an initial active-area efficiency of 10.9% and is stable against the ambient degradation. The stability data of the solar cells after light soaking are also presented.

EFFECTS OF INTERELECTRODE SPACING ON THE PROPERTIES OF MICROCRYSTALLINE SILICON ABSORBER AND SOLAR CELLS

2012 ◽  
Vol 1426 ◽  
pp. 105-110
Author(s):  
Bill Nemeth ◽  
Xiaodan Zhang ◽  
Yanfa Yan ◽  
Qi Wang
Keyword(s):  
Solar Cells ◽  
Growth Parameters ◽  
Short Circuit ◽  
Chemical Vapor ◽  
Short Circuit Current ◽  
Precursor Chemistry ◽  
Short Circuit Current Density ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Si Films

ABSTRACTWe study the effect of the spacing between electrodes in very high frequency plasma enhanced chemical vapor deposition on the properties of microcrystalline silicon films and their related n-i-psolar cells. We vary the spacing from 0.2 to 1.0 cm to deposit microcrystalline silicon at 67.8 MHz while maintaining other growth parameters. The spacing between the electrodes significantly changes the plasma conditions, which govern film precursor chemistry as well as introduce etching and ion bombardment to the film; thereby, influencing nucleation and growth of the microcrystalline Si films. The resulting films were characterized by UV-Vis spectrometry, atomic force microscopy, X-ray diffraction, and transmission electron microscopy. We found that deposition rate decreases, while surface roughness and short circuit current density increase with smaller spacing.

Hydrogenated Microcrystalline Silicon Single-Junction and Multi-Junction Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Baojie Yan ◽  
Guozhen Yue ◽  
Jeffrey Yang ◽  
Arindam Banerjee ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Glow Discharge ◽  
Silicon Germanium ◽  
Active Area ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Hydrogenated Silicon ◽  
Area Efficiency ◽  
Bottom Cell

AbstractThis paper summarizes our recent studies of hydrogenated microcrystalline silicon (μc-Si:H) solar cells as a potential substitute for hydrogenated silicon germanium alloy (a-SiGe:H) bottom cells in multi-junction structures. Conventional radio frequency (RF) glow discharge is used to deposit hydrogenated amorphous silicon (a-Si:H) and μc-Si:H at low rates (∼ 1 Å/s), searching for the highest efficiency. We have achieved an initial active-area efficiency of 13.0% and stable efficiency of 11.2% using an a-Si:H/μc-Si:H double-junction structure. Modified very high frequency (MVHF) glow discharge is used to deposit a-Si:H and μc-Si:H at high rates (∼ 3-10 Å/s) for comparison with our a-Si:H/a-SiGe:H/a-SiGe:H triple-junction production technology. The deposition time for the μc-Si:H intrinsic (i) layer in the bottom cell should be less than 30 minutes in order to be acceptable for mass production. To date, an initial active-area efficiency of 12.3% has been achieved with the bottom cell deposited in 50 minutes. By increasing the deposition rate and reducing the bottom cell thickness, we have achieved an initial active-area efficiency of 11.4% with the bottom cellilayer deposited in 30 minutes. The cell stabilized to 10.4% after prolonged light soaking. We will address issues related to μc-Si:H material, solar cell design, solar cell analysis, and stability.

Large-Area Hydrogenated Amorphous and Microcrystalline Silicon Double-Junction Solar Cells

2004 ◽  
Vol 808 ◽  
Author(s):  
Baojie Yan ◽  
Guozhen Yue ◽  
Arindam Banerjee ◽  
Jeffrey Yang ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Deposition Time ◽  
High Rate ◽  
Microcrystalline Silicon ◽  
Large Area ◽  
Area Efficiency ◽  
Rf Glow Discharge ◽  
Double Junction ◽  
Junction Structure ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon ( c-Si:H) double-junction solar cells were deposited on a large-area substrate using a RF glow discharge technique at various rates. The thickness uniformity for both a-Si:H and c-Si:H is well within ± 10% and the reproducibility is very good. Preliminary results from the large-area a-Si:H/m c-Si:H double-junction structures show an initial aperture-area efficiency of 11.8% and 11.3%, respectively, for 45 cm2 and 461 cm2 size un-encapsulated solar cells. The 11.3% cell became 10.6% after encapsulation and stabilized at 9.5% after prolonged light soaking under 100 mW/cm2 of white light at 50°C. High rate deposition of the c-Si:H layer in the bottom cell was made using the high-pressure approach. An initial active-area (0.25 cm2) efficiency of 11.3% was achieved using an a-Si:H/m c-Si:H double-junction structure with 50 minutes of c-Si:H deposition time.

scholarly journals Light Scattering and Current Enhancement for Microcrystalline Silicon Thin-Film Solar Cells on Aluminium-Induced Texture Glass Superstrates with Double Texture

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yunfeng Yin ◽  
Nasim Sahraei ◽  
Selvaraj Venkataraj ◽  
Sonya Calnan ◽  
Sven Ring ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Optical Scattering ◽  
Thin Film Solar Cells ◽  
Surface Topology ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Wide Range

Microcrystalline silicon (μc-Si:H) thin-film solar cells are processed on glass superstrates having both micro- and nanoscale surface textures. The microscale texture is realised at the glass surface, using the aluminium-induced texturing (AIT) method, which is an industrially feasible process enabling a wide range of surface feature sizes (i.e., 700 nm–3 μm) of the textured glass. The nanoscale texture is made by conventional acid etching of the sputter-deposited transparent conductive oxide (TCO). The influence of the resulting “double texture” on the optical scattering is investigated by means of atomic force microscopy (AFM) (studying the surface topology), haze measurements (studying scattering into air), and short-circuit current enhancement measurements (studying scattering into silicon). A predicted enhanced optical scattering efficiency is experimentally proven by a short-circuit current enhancementΔIscof up to 1.6 mA/cm2(7.7% relative increase) compared to solar cells fabricated on a standard superstrate, that is, planar glass covered with nanotextured TCO. Enhancing the autocorrelation length (or feature size) of the AIT superstrates might have the large potential to improve theμc-Si:H thin-film solar cell efficiency, by reducing the shunting probability of the device while maintaining a high optical scattering performance.

Light Management Using Periodic Textures for Enhancing Photocurrent and Conversion Efficiency in Thin-Film Silicon Solar Cells

2013 ◽  
Vol 1536 ◽  
pp. 3-15 ◽  
Author(s):  
Hitoshi Sai ◽  
Takuya Matsui ◽  
Adrien Bidiville ◽  
Takashi Koida ◽  
Yuji Yoshida ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Aspect Ratio ◽  
Light Trapping ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Area Efficiency ◽  
Cell Thickness

ABSTRACTPeriodically textured back reflectors with hexagonal dimple arrays are applied to thin-film microcrystalline silicon (μc-Si:H) solar cells for enhancing light trapping. The period and aspect ratio of the honeycomb textures have a big impact on the photovoltaic performance. When the textures have a moderate aspect ratio, the optimum period for obtaining a high short circuit current density (JSC) is found to be equal to or slightly larger than the cell thickness. If the cell thickness exceeds the texture period, the cell surface tends to be flattened and texture-induced defects are generated, which constrain the improvement in JSC. Based on these findings, we have fabricated optimized μc-Si:H cells achieving a high active-area efficiency exceeding 11% and a JSC of 30 mA/cm2.

scholarly journals Wide-Gap p-μc-Si1-xOx:H Films and Their Application to Amorphous Silicon Solar Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Taweewat Krajangsang ◽  
Sorapong Inthisang ◽  
Aswin Hongsingthong ◽  
Amornrat Limmanee ◽  
Jaran Sritharathikhun ◽  
...  
Keyword(s):  
Solar Cells ◽  
Silicon Oxide ◽  
Short Circuit ◽  
Chemical Vapor ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Window Layer ◽  
Very High Frequency ◽  
Raman Scattering Spectroscopy ◽  
Wide Gap

Optimization of p-type hydrogenated microcrystalline silicon oxide thin films (p-μc-Si1-xOx:H) by very high frequency plasma enhanced chemical vapor deposition 40 MHz method for use as a p-layer of a-Si:H solar cells was performed. The properties of p-μc-Si1-xOx:H films were characterized by conductivity, Raman scattering spectroscopy, and spectroscopic ellipsometry. The wide optical band gap p-μc-Si1-xOx:H films were optimized by CO2/SiH4ratio and H2/SiH4dilution. Besides, the effects of wide-gap p-μc-Si1-xOx:H layer on the performance of a-Si:H solar cells with various optical band gaps of p-layer were also investigated. Furthermore, improvements of open circuit voltage, short circuit current, and performance of the solar cells by using the effective wide-gap p-μc-Si1-xOx:H were observed in this study. These results indicate that wide-gap p-μc-Si1-xOx:H is promising to use as window layer in a-Si:H solar cells.

Optics in Thin-film Silicon Solar Cells with Integrated Lamellar Gratings

2009 ◽  
Vol 1153 ◽  
Author(s):  
Rahul Dewan ◽  
Darin Madzharov ◽  
Andrey Raykov ◽  
Dietmar Knipp
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Incident Light ◽  
Short Circuit Current ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Diffracted Waves ◽  
Difference Time

AbstractLight trapping in microcrystalline silicon thin-film solar cells with integrated lamellar gratings was investigated. The influence of the grating dimensions on the short circuit current and quantum efficiency was investigated by numerical simulation of Maxwell’s equations by a Finite Difference Time Domain approach. For the red and infrared part of the optical spectrum, the grating structure leads to scattering and higher order diffraction resulting in an increased absorption of the incident light in the silicon thin-film solar cell. By studying the diffracted waves arising from lamellar gratings, simple design rules for optimal grating dimensions were derived.

Bifacial microcrystalline silicon solar cells with improved performance due to μc-SiOx:H doped layers

2014 ◽  
Vol 92 (7/8) ◽  
pp. 913-916 ◽  
Author(s):  
V. Smirnov ◽  
A. Lambertz ◽  
F. Finger
Keyword(s):  
Solar Cells ◽  
Silicon Oxide ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Microcrystalline Silicon ◽  
Improved Performance ◽  
Conversion Efficiencies ◽  
Insight Into

We present the development and application of n-type hydrogenated microcrystalline silicon oxide (μc-SiOx:H) in semitransparent bifacial microcrystalline silicon (μc-Si:H) solar cells. Semitransparent bifacial solar cells are of interest for a number of technical applications like building integration or concentrator devices, but also can offer new insight into solar cell properties due to the possibility to illuminate the cell from both sides. Appropriately selected μc-SiOx:H n-layers with low refractive index and high optical band gap allow the reduction of the reflection of the cells and improve short circuit current density (JSC) and conversion efficiencies. The quality of n-type μc-SiOx:H window layers is demonstrated in solar cells with highly reflective ZnO/Ag contacts. High JSC values of 24.8 mA/cm2 and efficiencies of 9.5% are obtained for 1 μm thick solar cells.

p-type Window Layers for pin Solar Cells Entirely Fabricated by Hot-Wire CVD

2001 ◽  
Vol 664 ◽  
Author(s):  
Urban Weber ◽  
Markus Koob ◽  
Chandrachur Mukherjee ◽  
D. Chandrashekhar ◽  
Rajiv O. Dusane
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Hydrocarbon Gases ◽  
Layer Deposition ◽  
The Stability ◽  
Direct Dissociation

ABSTRACTWe investigate a-SiC:H p-layer deposition for a-Si:H-based solar cells by Hot-Wire CVD using alternatively methane, ethane, and acetylene. Carbon incorporation in the film results from gas-phase reactions and not from direct dissociation at the hot filament for all hydrocarbon gases. Ethane can be dissociated more easily than methane allowing less extreme deposition conditions. With all types of materials the requirements of high dark conductivity and high band gap for the use as window layers in solar cells can be fulfilled. Highest conductivity is observed with ethane indicating a better network structure, which is supported by the IR signatures. A larger band gap (>2 eV) can be obtained at a similar conductivity with the use of acetylene. We compare these results with the utilization of [.proportional]c-Si:H p-layers. All types of p-layers are incorporated into pin solar cells. Methane- and ethane-based a-SiC:H-p-layers yield similar Voc and FF (∼850 mV and 72%). Acetylene-p-layer-based solar cells yield higher current and higher Voc (890 mV) but lower fill factor (∼67%). Microcrystalline p-layers improve Voc and FF up to 900 mV and 72%, respectively, however higher absorption leads to lower short circuit current and prevents an increase of initial efficiency beyond 8%. Using ethane for p-layer deposition, a significant improvement of the stability of all-Hot-Wire CVD pin solar cells is achieved.

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