A Wide Band Gap Boron-doped Microcrystalline Silicon Film Obtained with VHF Glow Discharge Method

2005 ◽  
Vol 872 ◽  
Author(s):  
Zhu feng ◽  
Zhao ying ◽  
Wei changcun ◽  
Zhang xiaodan ◽  
Gao yantao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Raman Spectra ◽  
Volume Fraction ◽  
Silicon Film ◽  
Window Layer ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Very High Frequency ◽  
Microcrystalline Silicon Film

AbstractA wide bandgap microcrystalline silicon film for the window layer of microcrystalline silicon thin film solar cells was obtained with very high frequency (VHF) glow discharge technology. The material was deposited on corning 7059 substrate at about 170 When H2/SiH4 was more than 100, Raman spectra showed that this material was highly crystallized, and no peak correlation with amorphous silicon was observed. This material showed strong n type before any intentional doping. We considered that the unintentional doping of oxygen and unpurified gases. The doping performance of this material was investigated by introducing B2H6 into the reacting gas. As increasing the rate of B2H6/SiH4 from zero to 0.5%, the conductivity changed from 10-1S.cm-1 (n type) to 10-8 S.cm-1 dramatically and than backed to 10-1 S.cm-1 (p type), which indicated that this material had excellent doping ability. Raman spectra also showed that the microstructure of these materials did not change obviously in this doping range. We gained the p-uc-Si:H film with thickness less than 30nm, and the conductivity was more than 10-2 S.cm-1, and crystalline volume fraction no less than 40%, the Egopt could be wider than 2.10eV. Using this p window layer in microcrystalline silicon solar cells with no ZnO rear reflection, the conversion efficiency was 8.30% (Voc=0.531V, Jsc=24.66mA/cm2, FF=63.41% ).

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.

Microstructure Evolution with Thickness and Hydrogen Dilution Profile in Microcrystalline Silicon Solar Cells

2004 ◽  
Vol 808 ◽  
Author(s):  
Baojie Yan ◽  
Guozhen Yue ◽  
Jeffrey Yang ◽  
Subhendu Guha ◽  
D. L. Williamson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Area Efficiency ◽  
Junction Solar Cell ◽  
Hydrogen Dilution ◽  
Back Reflectors

ABSTRACTHydrogenated microcrystalline silicon (m c-Si:H) solar cells with different thicknesses were deposited on specular stainless steel substrates and on textured Ag/ZnO back reflectors using RF and modified very high frequency glow discharge at various deposition rates. Raman spectra and X-ray diffraction patterns exhibit a significant increase of microcrystalline volume fraction and in grain size with film thickness. Atomic force microscopy reveals an increase in the size of microstructural features and the surface roughness with increasing thickness. Based on these results, we believe that the increase of the microcrystalline phase with thickness is the main reason for the deterioration of cell performance with the thickness of the intrinsic layer. To overcome this problem, we have developed a procedure of varying the hydrogen dilution ratio during deposition. Using this method, we have been successful in controlling the microstructure evolution and achieved an initial active-area efficiency of 8.4% for a c-Si:H single-junction solar cell, and 13.6% for an a-Si:H/a-SiGe:H/m c-Si:H triple-junction solar cell.

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.

Microcrystalline Silicon Solar Cell Deposited Using Modified Very-High-Frequency Glow Discharge and Its Application in Multi-junction Structures

2004 ◽  
Vol 808 ◽  
Author(s):  
Guozhen Yue ◽  
Baojie Yan ◽  
Jessica M. Owens ◽  
Jeffrey Yang ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Glow Discharge ◽  
Triple Junction ◽  
High Frequency ◽  
Active Area ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Bottom Cell ◽  
Junction Structure ◽  
Very High

ABSTRACTWe have used the modified very-high-frequency glow discharge technique to deposit hydrogenated microcrystalline silicon (m c-Si:H) solar cells at high rates for use as the bottom cell in a multi-junction structure. We have investigated c-Si:H single-junction, a-Si:H/ c-Si:H double-junction, and a-Si:H/a-SiGe:H/m c-Si:H triple-junction solar cells and achieved initial active area efficiencies of 7.7%, 12.5%, and 12.4%, respectively. Issues related to improving material properties and device structures are addressed. By taking advantage of a lower degradation in m c-Si:H than a-Si:H and a-SiGe:H alloys, we have minimized the light induced effect in multi-junction structures by designing a bottom-cell-limited current mismatching. As a result, we have obtained a stable active-area cell efficiency of 11.2% with an a-Si:H/a-SiGe:H/μ c-Si:H triple-junction structure.

Thin p-type Microcrystalline Silicon Film on Various Substrates

1996 ◽  
Vol 420 ◽  
Author(s):  
J. K. Rath ◽  
J. Wallinga ◽  
R. E. I. Schropp
Keyword(s):  
Thin Films ◽  
Spectral Response ◽  
Silicon Film ◽  
Window Layer ◽  
Microcrystalline Silicon ◽  
Uv Reflectance ◽  
Oxide Substrates ◽  
P Type ◽  
Made In ◽  
Microcrystalline Silicon Film

AbstractThin(<20nm) p-type microcrystalline silicon f'dms have been deposited by PECVD in an unusual parameter regime, specifically optimized for extremely thin films. High conductivity (>10.2 Scm−1) and low activation energy(<0.08eV) of thin films have been achieved on various metal oxide substrates i.e., Coming 7059 glass, SnO2:F, TiO2 and Ta2O5. Crystallinity was confirmed by Raman spectroscopy and UV reflectance. Deposition of p-μc-Si:H is possible on void rich films (a-SiC:H and low temperature deposited a-Si:H) but not on device quality a-Si:H. Cells made in a superstrate structure using p-μc-Si:H as the window layer directly on top of SnO2:F coated glass yielded 9.63% efficiency, with an improvement in the blue spectral response compared to the cell made with a- SiC:H(B) as window layer. Tandem cells (a-Si:H/a-Si:H) incorporating p-μc-Si:H along with n-μc- Si:H in the tunnel junction yielded 8.8% efficiency.

scholarly journals Grown Low-Temperature Microcrystalline Silicon Thin Film by VHF PECVD for Thin Films Solar Cell

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Shanglong Peng ◽  
Desheng Wang ◽  
Fuhua Yang ◽  
Zhanguo Wang ◽  
Fei Ma
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Short Circuit ◽  
High Growth ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Very High Frequency ◽  
Silicon Thin Films

Hydrogenated microcrystalline silicon thin films can be used to fabricate stable thin film solar cell, which were deposited by very high frequency plasma-enhanced chemical vapor deposition at low temperatures (~200°C). It has been found that the obtained film presented excellent structural and electrical properties, such as high growth rate and good crystallinity. With the decreasing of silane concentration, the optical gap and the dark conductivity increased, whereas the activation energy decreased. A reasonable explanation was presented to elucidate these phenomena. In addition, we fabricated p-i-n structure solar cells using the optimum microcrystalline silicon thin films, and preliminary efficiency of 4.6% was obtained for 1 μm thick microcrystalline silicon thin film solar cells with open-circuits voltage of 0.773 V and short-circuits current density of 12.28 mA/cm2. Future scope for performance improvement lies mainly in further increasing the short-circuit current.

Research on Nanocrystalline Silicon Film Solar Cells

2011 ◽  
Vol 347-353 ◽  
pp. 870-873
Author(s):  
Chun Rong Xue
Keyword(s):  
Grain Size ◽  
Solar Cells ◽  
Band Gap ◽  
Optical Band Gap ◽  
Volume Fraction ◽  
Silicon Film ◽  
Nanocrystalline Silicon ◽  
Processing Parameters ◽  
Crystalline Volume Fraction ◽  
Hydrogen Dilution

Nanocrystalline silicon film has become the research hit of today’ s P-V solar technology. It’s optical band gap was controlled through changing the grain size and crystalline volume fraction for the quanta dimension effect. The crystalline volume fraction in nc-Si:H is modulated by varying the hydrogen concentration in the silane plasma. Also, the crystallinity of the material increases with increasing hydrogen dilution ratio, the band tail energy width of the nc-Si:H concurrently decreases. Two sets of nc-Si:H solar cells were made with different layer thicknesss, their electronic and photonic bandgap, absorption coefficient, optical band gap, nanocrystalline grain size(D), and etc have been stuied. In addition, we discussed the relationship between the stress of nc-Si thin films and H2 ratio. At last nc-Si:H solar cells have been designed and prepared successfully in the optimized processing parameters.

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