N-Type Hydrogenated Microcrystalline Silicon Oxide Films and Their Applications in Micromorph Silicon Solar Cells

2011 ◽  
Vol 1321 ◽  
Author(s):  
Amornrat Limmanee ◽  
Songkiate Kittisontirak ◽  
Channarong Piromjit ◽  
Jaran Sritharathikhun ◽  
Kobsak Sriprapha
Keyword(s):  
Solar Cells ◽  
Silicon Oxide ◽  
Volume Fraction ◽  
Short Circuit ◽  
Oxide Films ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Microcrystalline Silicon ◽  
Shunt Resistance

ABSTRACTWe have prepared n-type hydrogenated microcrystalline silicon oxide films (n μc-SiO:H) and investigated their structural, electrical and optical properties. Raman spectra shows that, amorphous phase of the n μc-SiO:H films tends to increase when the CO2/SiH4 ratio increases from 0 to 0.28 resulting in a reduction of the crystalline volume fraction (Xc) from 70 to 12%. Optical bandgap (E04) becomes gradually wider while dark conductivity and refractive index (n) continuously drop with increasing CO2/SiH4 ratio. The n μc-SiO:H films have been practically applied as a n layer in top cell of a-SiO:H/μc-Si:H micromorph silicon solar cells. We found that, open circuit voltage (Voc) and fill factor (FF) of the cells gradually increased, while short circuit current density (Jsc) remained almost the same value with increasing CO2/SiH4 ratio for n top layer deposition up to 0.23. The highest initial cell efficiency of 10.7% is achieved at the CO2/SiH4 ratio of 0.23. The enhancement of the Voc is supposed to be due to a reduction of reverse bias at sub cell connection (n top/p bottom interface). An increase of shunt resistance (Rsh) which is caused by a better tunnel recombination junction contributes to the improvement in the FF. Quantum efficiency (QE) results indicate no difference between the cells using n top μc-SiO:H and the cells with n top μc-Si:H layers. These results reveal that, the n μc-SiO:H films in this study do not work as an intermediate reflector to enhance light scattering inside the solar cells, but mainly play a key role to allow ohmic and low resistive electrical connection between the two adjacent cells in the micromorph silicon solar cells.

scholarly journals Advantages of N-Type Hydrogenated Microcrystalline Silicon Oxide Films for Micromorph Silicon Solar Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Amornrat Limmanee ◽  
Songkiate Kittisontirak ◽  
Sorapong Inthisang ◽  
Taweewat Krajangsang ◽  
Jaran Sritharathikhun ◽  
...  
Keyword(s):  
Solar Cells ◽  
Silicon Oxide ◽  
Oxide Films ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Microcrystalline Silicon ◽  
Cell Efficiency ◽  
Bottom Interface ◽  
Hydrogenated Amorphous ◽  
Recombination Junction

We report on the development and application of n-type hydrogenated microcrystalline silicon oxide films (nμc-SiO:H) in hydrogenated amorphous silicon oxide/hydrogenated microcrystalline silicon (a-SiO:H/μc-Si:H) micromorph solar cells. The nμc-SiO:H films with high optical bandgap and low refractive index could be obtained when a ratio of carbon dioxide (CO2) to silane (SiH4) flow rate was raised; however, a trade-off against electrical property was observed. We applied the nμc-SiO:H films in the top a-SiO:H cell and investigated the changes in cell performance with respect to the electrical and optical properties of the films. It was found that all photovoltaic parameters of the micromorph silicon solar cells using the n topμc-SiO:H layer enhanced with increasing the CO2/SiH4ratio up to 0.23, where the highest initial cell efficiency of 10.7% was achieved. The enhancement of the open circuit voltage (Voc) was likely to be due to a reduction of reverse bias at subcell connection—n top/p bottom interface—and a better tunnel recombination junction contributed to the improvement in the fill factor (FF). Furthermore, the quantum efficiency (QE) results also have demonstrated intermediate-reflector function of the nμc-SiO:H films.

The influence of emitter resistance on the electrical parameters of mono- and multicrystalline silicon solar cells

2019 ◽  
Vol 36 (3) ◽  
pp. 90-94
Author(s):  
Barbara Swatowska ◽  
Piotr Panek ◽  
Dagmara Michoń ◽  
Aleksandra Drygała
Keyword(s):  
Solar Cells ◽  
Contact Resistance ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Multicrystalline Silicon ◽  
Silicon Solar Cells ◽  
Electrical Parameters ◽  
Content Type ◽  
Diffusion Parameters

Purpose The purpose of this study was the comparison and analysis of the electrical parameters of two kinds of silicon solar cells (mono- and multicrystalline) of different emitter resistance. Design/methodology/approach By controlling of diffusion parameters, silicon mono- (Cz-Si) and multicrystalline (mc-Si) solar cells with different emitter resistance values were produced – 22 and 48 Ω/□. On the basis of current-voltage measurements of cells and contact resistance mapping, the properties of final solar cells based on two different materials were compared. Additionally, the influence of temperature on PV cells efficiency and open circuit voltage (Uoc) were investigated. The PC1D simulation was useful to determine spectral dependence of external quantum efficiency of solar cells with different emitter resistance. The silicon solar cells of 25 cm2 area and 240 µm thickness were investigated. Findings Considering the all stages of cell technology, the best structure is silicon solar cell with sheet resistance (Rsheet) of 45-48 Ω/□. Producing of an emitter with this resistance allowed to obtain cells with a fill factor between 0.725 and 0.758, Uoc between 585 and 612 mV, short circuit current (Isc) between 724 and 820 mA. Originality/value Measurements and analysis confirmed that mono- and multicrystalline silicon solar cells with 48 Ω/□ emitter resistance have better parameters than cells with Rsheet of 22 Ω/□. The contact resistance is the highest for mc-Si with Rsheet of 48 Ω/□ and reaches the value 3.8 Ωcm.

The Effect of Al-BSF on Seff and Rb in Industrialized Mono-Silicon Solar Cells

2012 ◽  
Vol 472-475 ◽  
pp. 1846-1850
Author(s):  
Shan Shan Dai ◽  
Gao Jie Zhang ◽  
Xiang Dong Luo ◽  
Jing Xiao Wang ◽  
Wen Jun Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Short Circuit ◽  
Rear Surface ◽  
Surface Recombination ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Silicon Solar Cells ◽  
Back Surface

In this work, the effect of aluminum back surface field formed by screen printed various amount of Al paste on the effective rear surface recombination velocity (Seff) and the internal rear reflectance coeffeicient (Rb) of commercial mono-silicon solar cells was investigated. We demonstrated the effect of Seffand Rbon the performance of Al-BSF solar cells by simulating them with PC1D. The simulated results showed that the lower Seffcould get higher open circuit voltage (Voc), at the same time, the larger Rbcould get higher short-circuit current (Isc). Experimentally, we investigated the Seffand Rbthrough depositing Al paste with various amount (3.7, 5, 6, and 8 mg/cm2) for fabricating Al-BSF mono-silicon solar cells. Four group cells were characterized by light I-V, spectral response, hemispherical reflectance and scanning electron microscope (SEM) measurements. It was found that, a minimum Seffof 350 cm/s was gotten from the cells with Al paste of 8 mg/cm2, which was extracted by matching quantum efficiency (QE) from 800 nm to 1200 nm with PC1D, and a maximum Rbof 53.5% was obtained from Al paste of 5 mg/cm2by calculating at 1105 nm with PC1D. When the amount of Al paste was higher than 5mg/cm2, there were less Seffand lower Rb. On the other hand, when Al amount was 3.7mg/cm2, it was too little to form a closed BSF. Based on the SEM graphs and simulations with PC1D, a simple explaination was proposed for the experimental results.

Study on the Performance of Aluminum Thick Film Contacts for Silicon Solar Cells

2013 ◽  
Vol 833 ◽  
pp. 241-246
Author(s):  
Ming Fu ◽  
Hong Yong Li ◽  
Gong Lei Jin ◽  
Lin Fan ◽  
Dong Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Thick Film ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Back Surface ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Photoelectric Properties

Aluminum rear contacts of silicon solar cells are made commonly by screen-printing aluminum paste and sintering process. Aluminum thick film contacts have a direct effect on photoelectric properties of solar cells, like open circuit voltage (Voc), short circuit current (Isc), conversion efficiency (η), etc. The principle of Al-back surface field (BSF) has been studied in this paper. With thermal gravimetric analysis and differential scanning calorimetry (TGA-DSC) method, the chemical reactions between aluminum thick film and silicon substrate during heat treatment have been investigated. The microstructure of aluminum thick film contacts were analysed by SEM. The electrical properties of Al-BSF are improved by adding a proper amount of nano silicon to the aluminum paste.

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.

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.

Equivalent-circuit Modeling of Microcrystalline Silicon pin Solar Cells prepared over a Wide Range of Absorber-layer Compositions

2010 ◽  
Vol 1245 ◽  
Author(s):  
Steve Reynolds ◽  
Vladimir Smirnov
Keyword(s):  
Solar Cells ◽  
Equivalent Circuit ◽  
Volume Fraction ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Crystalline Region ◽  
Photovoltaic Properties ◽  
Wide Range ◽  
Low Crystalline

AbstractAn equivalent-circuit electrical model is used to simulate the photovoltaic properties of mixed-phase thin-film silicon solar cells. Microcrystalline and amorphous phases are represented as separate parallel-connected photodiode equivalent circuits, scaled by assuming that the photodiode area is directly proportional to the volume fraction of each phase. A reasonable correspondence between experiment and simulation is obtained for short-circuit current and open-circuit voltage vs. volume fraction. However the large dip in fill-factor and reduced PV efficiency measured for cells prepared in the low-crystalline region is inadequately reproduced. It is concluded that poor PV performance in this region is not due solely to shunting by more highly-crystalline filaments, which supports the view that the low-crystalline material has transport properties inferior to either microcrystalline or amorphous silicon.

A Carrier Lifetime Model for the Optical Degradation of Amorphous Silicon Solar Cells

1985 ◽  
Vol 49 ◽  
Author(s):  
Z E. Smith ◽  
S. Wagner
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Carrier Lifetime ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Carrier Lifetimes ◽  
Bond Density ◽  
Degradation Data

AbstractThe light-induced performance degradation of amorphous silicon solar cells is described well by a model in which the carrier lifetimes are determined by the dangling bond density. The kinetics of the defect generation follow the model in which band-to-band recombination provides the energy for the creation of dangling bonds, which in turn introduce gap states that reduce carrier lifetime. Degradation will be slower in solar cells operating at lower excess carrier concentrations. This is documented with a comparison of degradation data for cells of different i-layer thickness, cells operating at open circuit vs. load, and for single vs. cascade cells. The model also correctly predicts the relation between short circuit current and fill factor degradation. At sufficiently long times, the efficiency will decrease at approximately the same rate for all cell structures and dimensions, with an offset in time between different device types which can be calculated.

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