Material Basis of Highly Stable a-Si:H Solar Cells

1996 ◽  
Vol 420 ◽  
Author(s):  
B. Rech ◽  
S. Wieder ◽  
F. Siebke ◽  
C. Beneking ◽  
H. Wagner
Keyword(s):  
Defect Density ◽  
Short Circuit ◽  
Short Circuit Current ◽  
High Hydrogen ◽  
Interface Recombination ◽  
Hydrogen Dilution ◽  
Process Gas ◽  
Current Densities ◽  
Comprehensive Characterization

AbstractWe achieved a stabilized efficiency of 9.2 % after only 8 % relative degradation for an a-Si:H/a-Si:H stacked cell with the top-cell i-layer prepared at 140 °C using a high hydrogen dilution of the silane process gas. From a comprehensive characterization of p-i-n cells and the corresponding i-layer material prepared at 140 °C and 190 °C substrate temperature with different hydrogen dilutions, we conclude that the performance of these pin cells strongly correlates with the material properties of the corresponding i-layers. High fill factors after light soaking are reflected in a good microstructure, high photo-conductivity, and relatively low defect density. Whereas the initial Voc is limited by interface recombination, volume recombination dominates the forward-dark current after light soaking. The stabilized Voc as well as the short-circuit current densities correlate with the optical bandgap of the i-layer.

Microcrystalline Germanium Photodetectors

2001 ◽  
Vol 664 ◽  
Author(s):  
M. Krause ◽  
H. Stiebig ◽  
R. Carius ◽  
H. Wagner
Keyword(s):  
Electronic Properties ◽  
Near Infrared ◽  
Short Circuit ◽  
Chemical Vapor ◽  
Short Circuit Current ◽  
Infrared Light ◽  
High Hydrogen ◽  
Sensor Applications ◽  
Hydrogen Dilution ◽  
Structural And Electronic Properties

ABSTRACTFor sensor applications in the detection of near infrared light we have prepared μc-Ge:H by plasma enhanced chemical vapor deposition (PECVD) with a mixture of germane and hydrogen, investigatedits structural and electronic properties and incorporated it into thin pin diodes. In order to ensure microcrystalline growth we had to use high hydrogen dilution. However, only the material prepared with a ratio of germane to hydrogen of 0.2% shows high crystallinity. The optical absorption is remarkably different from c-Ge and exhibits no indication of a direct gap at 0.8eV. When this material is implemented as part of a 110nm thin absorber, a short circuit current of 20mA/cm2 and a quantum efficiency of 15% at a wavelength of 1.1μm are achieved. Higher germane concentrations in hydrogen lead to poor electronic properties due to an increase of the amorphous phase and the short circuit current of the devices deteriorates. As for crystalline germanium photodiodes cooling of the devices is used to overcome the restrictionoriginating from the high free carrier concentration.

Electronic and Structural Characterization of the Near Surface Layer and the Bulk in νc-Si:H Prepared with Hydrogen dilution

1989 ◽  
Vol 164 ◽  
Author(s):  
Samer Aljishi ◽  
Shu Jin ◽  
Martin Stutzmann ◽  
Lothar Ley
Keyword(s):  
Hydrogen Bonding ◽  
Surface Layer ◽  
Optical Absorption ◽  
Structural Characterization ◽  
Defect Density ◽  
Total Yield ◽  
High Hydrogen ◽  
Near Surface ◽  
Hydrogen Dilution

AbstractThe near surface layer and the bulk of νc-Si:H prepared with hydrogen dilution are investigated by Raman, optical absorption, and total yield photoelectron spectroscopies. The results show that for low hydrogen dilution ratios, microcrystallites appear in the bulk while the growing surface layer remains amorphous, indicating that microcrystallite formation takes place primarily in the sub-surface layer. At high hydrogen dilution ratios, microcrystallites are detected at both the bulk and the near surface layer. The defect density and hydrogen bonding configurations at various hydrogen dilution levels are presented.

Hot-Wire CVD Poly-Silicon Films for Thin Film Devices

1998 ◽  
Vol 507 ◽  
Author(s):  
J.K. Rath ◽  
F.D. Tichelaar ◽  
H. Meiling ◽  
R.E.I. Schropp
Keyword(s):  
Defect Density ◽  
Initial Growth ◽  
Oriented Growth ◽  
Compact Structure ◽  
High Hydrogen ◽  
New Approach ◽  
Intrinsic Nature ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Long Duration

ABSTRACTSolar cell using profiled poly-Si:H by HWCVD as i-layer in the configuration SS/n-µSi:H(PECVD)/i-poly-Si:H(HWCVD)/p-µc-Si:H(PECVD)/ITO showed 3.7% efficiency. A current of 23.6 mA/cm2 was generated in only 1.5 µm thick poly-Si:H i-layer grown at ∼5Å/s. TFTs made with the poly-Si:H films (grown at ≥ 9Å/s) exhibited remarkable stability to long duration of 23 hours of gate bias stress of ∼lMV/cm. A saturation mobility of 1.5 cm2/Vs for the TFT has been achieved. Films made at low hydrogen dilution (Poly2) showed device quality (purely intrinsic nature, ambipolar diffusion length of 568 nm, only (220) oriented growth and low ESR defect density of <1017/cm3with complete absence of signal due to conduction electrons) but with an incubation phase of amorphous initial growth, whereas the films made at high hydrogen dilution (Polyl) had a polycrystalline initial growth, though with higher defect density, incorporated oxygen and randomly oriented grains. Poly2 films are compact and hydrogen bonding is at compact Si-H sites manifested as 2000 cm−1IR vibration and high temperature hydrogen evolution peak. Exchange interaction of spins and spin pairing are observed while increasing defects in such a compact structure. A new approach has been used to integrate these two regimes of growth to make profiled poly-Si:H layers. The new layers show good electronic properties as well as complete elimination of incubation phase.

Solar Cell Contacts Using Nano-Sized Dispersions

1999 ◽  
Vol 581 ◽  
Author(s):  
Doug Schulz ◽  
R. Ribelin ◽  
X. Wu ◽  
K.M. Jones ◽  
R.J. Matson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spray Deposition ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cdte Layer ◽  
Open Circuit ◽  
Alloy Formation ◽  
Current Densities ◽  
P Type ◽  
Open Circuit Voltages

ABSTRACTNano-sized dispersions have been employed as precursor inks for the spray deposition of contacts to both Si and CdTe materials. In the case of Si, nano-sized Al particles (nano-Al) were dispersed and spray deposited onto p-type Si. Annealing above the eutectic temperature causes alloy formation yielding a p+ layer with p ∼ 10−4 Ω•cm. For CdTe, nano-sized Te particles (nano-Te) were dispersed and sprayed onto CdTe/CdS/SnO2/glass heterostructures. Contact to the CdTe layer occurred during a 30 min anneal in He (T = 215 to 255 °C). These solar cells were finished by spin-coating the Te layer with Ag paint and subsequently annealing in air (100 °C / 1 h). This approach produces solar cells with open circuit voltages (Voc) from 720 to 800 mV, short circuit current densities (Jsc) from 18 to 20 mA/cm2 and efficiencies up to 10.3%. The performance of these cells was similar to those produced using the standard NREL contact.

scholarly journals Toward Current Matching in Tandem Dye-Sensitized Solar Cells

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2936
Author(s):  
Junfeng Wei ◽  
Zhipeng Shao ◽  
Bin Pan ◽  
Shuanghong Chen ◽  
Linhua Hu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Short Circuit Current ◽  
Dye Sensitized ◽  
Current Matching ◽  
Current Densities ◽  
Experimental Findings ◽  
Photovoltaic Technologies ◽  
Sensitized Solar Cells

The tandem pn-type dye-sensitized solar cells (pn-DSCs) have received much attention in the field of photovoltaic technologies because of their great potential to overcome the Shockley-Queisser efficiency limitation that applies to single junction photovoltaic devices. However, factors governing the short-circuit current densities (Jsc) of pn-DSC remain unclear. It is typically believed that Jsc of the pn-DSC is limited to the highest one that the two independent photoelectrodes can achieve. In this paper, however, we found that the available Jsc of pn-DSC is always determined by the larger Jsc that the photoanode can achieve but not by the smaller one in the photocathode. Such experimental findings were verified by a simplified series circuit model, which shows that a breakdown will occur on the photocathode when the photocurrent goes considerably beyond its threshold voltage, thus leading to an abrupt increase in Jsc of the circuit. The simulation results also suggest that a higher photoconversion efficiency of the pn-DSCs can be only achieved when an almost equivalent photocurrent is achieved for the two photoelectrodes.

Covalent modification and inhibition of an epithelial sodium channel by tyrosine-reactive reagents

1980 ◽  
Vol 239 (3) ◽  
pp. F299-F306 ◽  
Author(s):  
C. S. Park ◽  
D. D. Fanestil
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Complete Recovery ◽  
Covalent Modification ◽  
Na Channel ◽  
Chemical Probes ◽  
Pharmacologic Activity ◽  
Identification And Characterization ◽  
Aerobic And Anaerobic

This study sought to elucidate the molecular mechanism involved in the Na+ entry across the apical membrane of the urinary bladder of the toad. Na+ transport, as measured by short-circuit current (SCC), was irreversibly inhibited by three tyrosine-specific reagents: N-acetylimidazole (ID50, 4.6 x 10(-2)M), tetranitromethane (1.8 x 10(-4) M), and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl; 3.4 x 10(-5) M). The functional specificity of NBD-Cl to block Na+ entry via Na+ channels was attested by the following: 1) NBD-Cl produced comparable inhibition of SCC and Na+ influx under aerobic and anaerobic conditions; 2) amphotericin B produced complete recovery of inhibited SCC; 3) vasopressin increased SCC only in proportion to the uninhibited SCC; 4) Km for Na+ was not changed; and 5) the half time for the inhibition varied as a function of amiloride concentration or pharmacologic activity of its analogues. On the basis of the above findings, these tyrosine-specific reagents are believed to be useful chemical probes for the identification and characterization of Na+ channel protein.

Thermodynamic limits of nanophotonic light trapping in thin film silicon solar cells

2014 ◽  
Vol 92 (7/8) ◽  
pp. 909-912 ◽  
Author(s):  
Brian R. Maynard ◽  
E.A. Schiff
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Thin Film Silicon ◽  
Solar Tracking ◽  
Current Densities ◽  
Thermodynamic Limits

We have extended an earlier thermodynamic treatment of light-trapping in lattice-textured solar cells to higher absorptances. This treatment is used to calculate the quantum efficiency spectra and short-circuit current densities JSC for thin-film silicon solar cells with ideal lattice textures. An optimal triangular lattice period of 900 nm yields a calculated JSC that is 2 mA/cm2 larger than for ideal random textures in a 1000 nm thick cell. We compare the calculations to recent experiments with periodically textured cells. While the experimental cells give JSC values that are comparable to the best cells with conventional textures, they do not show the features associated with the prediction of higher JSC. We discuss the role of imperfections in the periodic texturing, and suggest that cells used with solar tracking may realize the predicted JSC improvement.

scholarly journals Preparation and Study of CdO-CdO2 Nanoparticles for Solar Cells Applications

2016 ◽  
Vol 69 ◽  
pp. 34-41
Author(s):  
Muneer H. Jadduaa ◽  
Nadir Fadhil Habubi ◽  
Alaa Z. Ckal
Keyword(s):  
Thin Film ◽  
Energy Gap ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Casting Technique

—In this study, (CdO) thin film, which was prepared by chemical method and deposited by drop casting technique on glass and silicon substrates have been studied . The structural, optical and chemical analysis were investigated. X-ray diffraction (XRD) measurements reveal that the (CdO) thin film was polycrystalline, cubic structure and there is no trace of the other material. UV-Vis measurements assure that the energy gap of (CdO) thin film was found to be 2.5eV. I-V characterization of the solar cell under illumination at 40mW/cm2 fluence was investigated . The open circuit voltage (Voc) was 4.1V and short-circuit current density (Isc) was 1.44 mA. These measurements show that the fill factor (FF) and the conversion efficiency (η) ,were 36.2% and 6.8% respectively.

Short Circuit Ruggedness of 600 V SiC Trench JFETs

2020 ◽  
Vol 1004 ◽  
pp. 933-938
Author(s):  
Vinoth Sundaramoorthy ◽  
Lukas Kranz ◽  
Stephan Wirths ◽  
Marco Bellini ◽  
Gianpaolo Romano ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Power ◽  
Operating Temperature ◽  
Short Circuit ◽  
Short Circuit Current ◽  
State Resistance ◽  
Resistance Value ◽  
A Current ◽  
Short Circuit Condition

Silicon Carbide JFETs with low on-state resistance are suitable for a number of high power applications. The static, dynamic and short circuit characterization of 600 V SiC Trench JFETs are reported in this paper. Typical JFETs fabricated with a 1.2 μm cell pitch had an on-resistance value around 40 mΩ and blocking voltages of ~600 V across the wafer. JFETs were successfully switched with a dc link voltage of 300 V, a current of 15 A and operating temperature of 125 °C. These JFETs were subjected to a short circuit condition with duration ranging from 10 μs to 45 μs at a dc link voltage of ~300 V, and operating temperatures of 25 °C and 125 °C. The device could withstand subsequent short circuit successfully without any failure at both 25 °C and 125 °C. The short circuit current showed consistent dependency on the applied gate voltage, when it was varied from 0 V to 15 V.

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