Electronic Characterization and Light-Induced Degradation in nc-Si:H Solar Cells

2006 ◽  
Vol 910 ◽  
Author(s):  
P. G. Hugger ◽  
Shouvik Datta ◽  
P. T. Erslev ◽  
Guozhen Yue ◽  
Gautam Ganguly ◽  
...  
Keyword(s):  
Minority Carrier ◽  
Volume Fraction ◽  
Nanocrystalline Silicon ◽  
Drive Level ◽  
Transient Photocurrent ◽  
Back Reflectors ◽  
Crystallite Sizes ◽  
Carrier Collection ◽  
Conversion Efficiencies ◽  
Steel Substrates

AbstractThe electronic properties of working nanocrystalline silicon (nc-Si:H) solar cell devices with conversion efficiencies up to 8.6% were studied using junction capacitance methods. The set of devices examined were deposited on both specular stainless steel substrates and Ag/ZnO textured back reflectors. These devices included nc-Si:H grown under constant H2 dilution, and also with profiled H2 dilution to control the crystallite sizes and volume fraction. Transient photocapacitance and transient photocurrent spectroscopies were used to obtain sub-band-gap optical spectra. A comparison of these two kinds of spectra also allowed us to deduce the minority carrier collection fractions as a function of temperature and light-induced degradation. Light-soaking was found to cause a distinct decrease in minority carrier collection, as well as a consistent decrease in defects responding to drive-level capacitance profiling. A tentative microscopic model is proposed that accounts for these degradation effects in nc-Si:H.

The Effects of Hydrogen Profiling and of Light-Induced Degradation on the Electronic Properties of Hydrogenated Nanocrystalline Silicon

2005 ◽  
Vol 862 ◽  
Author(s):  
A.F. Halverson ◽  
J.J. Gutierrez ◽  
J.D. Cohen ◽  
Baojie Yan ◽  
Jeffrey Yang ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Minority Carrier ◽  
Defect Density ◽  
Light Exposure ◽  
Nanocrystalline Silicon ◽  
Drive Level ◽  
Dramatic Decrease ◽  
Transient Photocurrent ◽  
Hydrogen Dilution ◽  
Carrier Collection

AbstractThe electronic properties of hydrogenated nanocrystalline silicon (nc-Si:H) were studied using junction capacitance methods. Drive-level capacitance profiling (DLCP) measurements revealed significant differences for nc-Si:H layers deposited under constant hydrogen dilution compared to those deposited using hydrogen profiling, with lower DLCP densities in the latter case. Transient photocapacitance (TPC) measurements revealed the mixed-phase nature of these materials. It disclosed spectra that appeared quite microcrystalline-like at lower temperatures, but more similar to a-Si:H at higher temperatures where the minority carrier collection is higher in the nanocrystalline component of these samples. This then suppresses the TPC signal from this component compared to the a-Si:H component. In contrast, because transient photocurrent signals are enhanced by the additional minority carrier collection, those spectra appear microcrystalline like at all temperatures. We also investigated the effects of light-induced degradation in these devices. This caused a dramatic decrease in hole collection, similar to that caused by reducing the measurement temperature of the samples. However, the light exposure did not appear to increase the deep defect density (dangling bonds).

Electronic Properties Of Nanocrystalline Silicon Deposited With Different Crystallite Fractions And Growth Rates

2008 ◽  
Vol 1066 ◽  
Author(s):  
Peter G. Hugger ◽  
J. David Cohen ◽  
Baojie Yan ◽  
Guozhen Yue ◽  
Xixiang Xu ◽  
...  
Keyword(s):  
Minority Carrier ◽  
Volume Fraction ◽  
Nanocrystalline Silicon ◽  
Drive Level ◽  
Crystalline Volume Fraction ◽  
Capacitance Measurements ◽  
Transient Photocurrent ◽  
Spatially Resolved ◽  
Before And After ◽  
Defect Densities

ABSTRACTJunction capacitance measurements were used to characterize the properties of nanocrystalline silicon (nc-Si:H) solar cells. These methods included drive-level capacitance profiling (DLCP) to obtain spatially-resolved defect densities, as well as transient photocapacitance (TPC) and transient photocurrent (TPI) spectra to reveal optically responsive states in the band-gap, and to estimate minority carrier behavior before and after lightsoaking. Crystalline volume fractions were estimated using Raman spectroscopy. Previously we had identified at least two types of distinct behaviors in such nc-Si:H materials that depended on the crystalline volume fraction. Here, in one case, we report results indicating that both types of behavior can occur in a single sample, possibly indicating that the structural properties of that sample have evolved during growth.

The mean crystallite size within a hydrogenated nanocrystalline silicon based photovoltaic solar cell and its role in determining the corresponding crystalline volume fraction

2014 ◽  
Vol 92 (7/8) ◽  
pp. 857-861 ◽  
Author(s):  
K.J. Schmidt ◽  
Y. Lin ◽  
M. Beaudoin ◽  
G. Xia ◽  
S.K. O’Leary ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Volume Fraction ◽  
Nanocrystalline Silicon ◽  
Crystalline Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Photovoltaic Solar Cell ◽  
Crystallite Sizes ◽  
The Mean ◽  
Silicon Based

We examine the dependence of the crystalline volume fraction on the mean crystallite size for hydrogenated nanocrystalline silicon based photovoltaic solar cells; this work builds upon an earlier study by Schmidt et al. (Mater. Res. Soc. Symp. Proc. 1536 (2013)). For each photovoltaic solar cell considered, the X-ray diffraction and Raman spectra are measured. Through the application of Scherrer’s equation, the X-ray diffraction results are used to determine the corresponding mean crystallite sizes. Through peak decomposition, the Raman results are used to estimate the corresponding crystalline volume fraction. Plotting the crystalline volume fraction as a function of the mean crystallite size, it is found that larger mean crystallite sizes tend to favor reduced crystalline volume fractions. The ability to randomly pack smaller crystallites with a greater packing fraction than their larger counterparts was suggested as a possible explanation for this observation.

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.

scholarly journals Properties of nanocrystalline silicon probed by optomechanics

Nanophotonics ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniel Navarro-Urrios ◽  
Martín F. Colombano ◽  
Jeremie Maire ◽  
Emigdio Chávez-Ángel ◽  
Guillermo Arregui ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Nonlinear Effects ◽  
Nanocrystalline Silicon ◽  
Nanoelectromechanical Systems ◽  
Mechanical And Thermal Properties ◽  
Quality Factors ◽  
Recombination Rates ◽  
Enhanced Absorption ◽  
Nanocrystallite Size ◽  
Crystallite Sizes

AbstractNanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimize their functionality for devices and applications. Here, we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through nonlinear optical and thermal processes. Promising optical (13,000) and mechanical (1700) quality factors were found in the optomechanical cavity realized in the nanocrystalline Si resulting from annealing at 950°C. The enhanced absorption and recombination rates via the intragap states and the reduced thermal conductivity boost the potential to exploit these nonlinear effects in applications including Nanoelectromechanical systems (NEMS), phonon lasing and chaos-based devices.

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.

Effects of Ga Compositional Grading on CIGS Electronic Properties Relevant to Solar Cell Performance

2009 ◽  
Vol 1165 ◽  
Author(s):  
JinWoo Lee ◽  
Jeroen K.J. van Duren ◽  
Alex Pudov ◽  
Miguel Contreras ◽  
David J. Cohen
Keyword(s):  
Solar Cell ◽  
Minority Carrier ◽  
Defect Density ◽  
Cell Performance ◽  
Solar Cell Performance ◽  
Free Hole ◽  
Deep Acceptor ◽  
Free Carrier Density ◽  
Carrier Collection ◽  
Compositional Grading

AbstractTransient photocurrent (TPI) and photocapacitance (TPC) spectroscopy have been applied to a set of compositional graded CuIn1-xGaxSe2 (CIGS) solar cell devices deposited by the vacuum co-evaporation method at the National Renewable Energy Laboratory. These measurements provide a spectral map of the optically induced release of carriers for photon energies from below 1 eV to 2 eV. By comparing the two types of spectra one can distinguish majority from minority carrier processes and they clearly reveal a higher degree of minority carrier collection for devices in which the Ga fraction increased monotonically with distance from the junction. This agrees with notions of how compositional grading improves overall cell performance. Minority carrier collection was even more strongly enhanced in sample devices incorporating v-shaped Ga-grading. Spatial profiles of the free hole carrier densities and deep acceptor concentrations were examined using drive-level capacitance profiling (DLCP). In the compositionally graded sample devices we found that the free carrier density decreased and that defect density increased with increasing Ga fraction toward back contact.

Influence of the Frontside Charge Inversion Layer on the Minority Carrier Collection in Backside Contacted Liquid Phase Crystallized Silicon on Glass Solar Cells

Solar RRL ◽  
2017 ◽  
Vol 1 (9) ◽  
pp. 1700100 ◽  
Author(s):  
Tim Frijnts ◽  
Natalie Preissler ◽  
Stefan Gall ◽  
Sebastian Neubert ◽  
Bernd Rech ◽  
...  
Keyword(s):  
Solar Cells ◽  
Liquid Phase ◽  
Minority Carrier ◽  
Inversion Layer ◽  
Charge Inversion ◽  
Carrier Collection

Influence of Powder Structure on Decarburization and Microstructure of HVOF Sprayed WC-12wt.%Co Coatings

2013 ◽  
Vol 834-836 ◽  
pp. 609-612 ◽  
Author(s):  
Ning Ma ◽  
Zhen Xiong Cheng ◽  
Huan Tao Wu ◽  
Fu Xing Ye
Keyword(s):  
Particle Size ◽  
Tungsten Carbide ◽  
Carbide Particle ◽  
Volume Fraction ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Spray System ◽  
Hvof Spray ◽  
Steel Substrates ◽  
Sprayed Coatings

In order to examine the influences of tungsten carbide particle size on decarburization behavior and microstructure of HVOF sprayed WC-Co coating, four kinds of agglomerated WC-12wt.%Co powders were deposited on mild steel substrates by using a high velocity oxy-fuel (HVOF) spray system. The phase compositions and microstructure of the feedstock powders and sprayed coatings were investigated by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), respectively. The results showed that the decarburization became more serious with the decreasing of tungsten carbide particle size in the starting powder. W phase was detected in the as-sprayed nanocomposite WC-12wt.%Co coating. All the coatings showed very compact microstructure with the hard phases embedded in Co matrix. The microstructure of HVOF sprayed WC-12wt.%Co coatings depended on the feedstock powder structure. The shape of tungsten carbide particles was rounder and the volume fraction of carbide phase decreased in coatings as the tungsten carbide particle size decreased.

Improvement of minority carrier collection and quantum efficiency in graphene planar silicon solar cell

2017 ◽  
Vol 49 (4) ◽  
Author(s):  
Yawei Kuang ◽  
Yulong Ma ◽  
Jian Xu ◽  
Yushen Liu ◽  
Debao Zhang ◽  
...  
Keyword(s):  
Solar Cell ◽  
Quantum Efficiency ◽  
Silicon Solar Cell ◽  
Minority Carrier ◽  
Planar Silicon ◽  
Carrier Collection
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