Dolts of Polysilicon for Solar Cell Applications

1986 ◽  
Vol 71 ◽  
Author(s):  
P.K. Mclarty ◽  
Y.I. Huang ◽  
D. E. Ioannou ◽  
S.M. Johnson
Keyword(s):  
Solar Cell ◽  
Grain Boundaries ◽  
Doping Level ◽  
Polycrystalline Silicon ◽  
Schottky Diodes ◽  
Casting Technique ◽  
P Type ◽  
Electron And Hole Traps ◽  
Dlts Spectra

AbstractDLTS was applied to p—type polycrystalline silicon, grown by a casting technique to form ingots with a nominal doping level of ∼1016 acceptors/cmg. Both Schottky diodes and n+p mesa structures were used for the measurements. Very complex DLTS spectra were obtained from diodes that contained electrically active grain boundaries, whereas no traps were detected in areas that did not contain electrically active grain boundaries. Several electron and hole traps were resolved.

Impurity thermovoltaic effect in the grain boundaries of a polycrystalline silicon solar cell

2007 ◽  
Vol 43 (4) ◽  
pp. 203-206 ◽  
Author(s):  
M. S. Saidov ◽  
B. M. Abdurakhmanov ◽  
L. O. Olimov
Keyword(s):  
Solar Cell ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Silicon Solar Cell ◽  
Thermovoltaic Effect

scholarly journals Analysis of Back Surface Field (BSF) Performance in P-Type And N-Type Monocrystalline Silicon Wafer

2018 ◽  
Vol 43 ◽  
pp. 01006 ◽  
Author(s):  
Ferdiansjah ◽  
Faridah ◽  
Kelvian Tirtakusuma Mularso
Keyword(s):  
Solar Cell ◽  
Doping Level ◽  
Short Circuit ◽  
Surface Recombination ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Surface Recombination Velocity ◽  
Back Surface ◽  
Solar Cell Performance ◽  
P Type

Back Surface Field (BSF) has been used as one of means to enhance solar cell performance by reducing surface recombination velocity (SRV). One of methods to produce BSF is by introducing highly doped layer on rear surface of the wafer. Depending on the type of the dopant in wafer, the BSF layer could be either p+ or n+. This research aims to compare the performance of BSF layer both in p-type and n-type wafer in order to understand the effect of BSF on both wafer types. Monociystalline silicon wafer with thickness of 300 μm. area of 1 cm2, bulk doping level NB = 1.5×1016/cm3 both for p-type wafer and n-type wafer are used. Both wafer then converted into solar cell by adding emitter layer with concentration NE =7.5×1018/cm3 both for p-type wafer and n-type wafer. Doping profile that is used for emitter layer is following complementary error function (erfc) distribution profile. BSF concentration is varied from 1×1017/cm3 to 1×1020/cm3 for each of the cell. Solar cell performance is tested under standard condition, with AM1.5G spectrum at 1000 W/m2. Its output is measured based on its open circuit voltage (Voc). short circuit current density (JSC), efficiency (η). and fill factor (FF). The result shows that the value of VOC is relatively constant along the range of BSF concentration, which is 0.694 V – 0.702 V. The same pattern is also observed in FF value which is between 0.828 – 0.831. On the other hand, value of JSC and efficiency will drop against the increase of BSF concentration. Highest JSC which is 0.033 A/cm2 and highest efficiency which is 18.6% is achieved when BSF concentration is slightly higher than bulk doping level. The best efficiency can be produced when BSF concentration is around 1×1017cm-3.. This result confirms that surface recombination velocity has been reduced due to the increase in cell’s short circuit current density and its efficiency. In general both p-type and n-type wafer will produce higher efficiency when BSF is applied. However, the increase is larger in p-type wafer than in n-type wafer. Better performance for solar cell is achieved when BSF concentration is slightly higher that bulk doping level because at very high BSF concentration the cell’s efficiency will be decreased.

Improved Electrical Properties in Nanocrystalline Si Formed by Metal Induced Growth

2003 ◽  
Vol 762 ◽  
Author(s):  
Chunhai Ji ◽  
Wayne A. Anderson
Keyword(s):  
Electrical Properties ◽  
Doping Level ◽  
Short Circuit ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Working Pressure ◽  
Si Films ◽  
P Type

AbstractIn recent work, the electrical properties of metal-induced-grown (MIG) Si thin films were studied by using current-voltage (I-V) data from a metal/Si Schottky contact. It was found that controlling the doping level of the films and annealing in forming gas (15% H2 and 85% N2) can improve the quality of the nc-Si films. From SIMS analysis on the nc-Si film deposited from a highly doped target, the nc-Si can duplicate the doping level of the sputtering target. Study of p-type doped nc-Si films showed that the fabrication of Schottky diodes on nc-Si films made from an extremely high-doped target (∼1020 cm-3) or low-doped target (∼1015cm-3) was not successful. For highly doped p-type films, tunneling causes Ohmic conduction instead of rectifying conduction. For the nc-Si film deposited from a low-doped p-type target, the film shows conversion to n-type characteristics when measured by a hot probe. This might be due to defects or oxygen in the film. N-type films at the middle doping level (∼1017cm-3) gave good Schottky diodes after annealing the film in forming gas at 700°C. The Schottky diodes fabricated by high work-function metal (Au) gave the rectifying ratio of ~∼103. Several techniques, e.g. slow/fast two-step sputtering at low working pressure and surface polishing, were used to improve the photo response of Schottky photodiodes. The open-circuit voltage (Voc) of 0.164V and short-circuit current density (Jsc) of 2.5 mA/cm2 were achieved under 100mW/cm2 illumination.

Impurity thermovoltaic effect in the grain boundaries of a polycrystalline silicon solar cell

2007 ◽  
Vol 43 (4) ◽  
pp. 203-206 ◽  
Author(s):  
M. S. Saidov ◽  
B. M. Abdurakhmanov ◽  
L. O. Olimov
Keyword(s):  
Solar Cell ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Silicon Solar Cell ◽  
Thermovoltaic Effect

Grain Boundary Passivation in Polycrystalline Silicon : A D.L.T.S. Study

1981 ◽  
Vol 5 ◽  
Author(s):  
Prakash C. Srivastava ◽  
Jacques C. Bourgoin
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Cross Section ◽  
Polycrystalline Silicon ◽  
Capture Cross Section ◽  
Narrow Band ◽  
Total Density ◽  
Capture Cross ◽  
Deuterium Plasma ◽  
P Type

ABSTRACTAfter treatment in a deuterium plasma, the D.L.T.S. spectrum associated with grain boundaries in p–type Si is found to reduce to a narrow band centered at 0.32 ± 0.02 eV with a total density of 5 ⨉ 1015 cm−2 . However, the capture cross-section, measured to be ∼ 2 × 10−20 cm2 , is 10 times larger than the apparent cross-section associated with the states present in unpassivated material.

EBIC Investigation of the Influence of Hydrogen Passivation on Thin-Film Polycrystalline Silicon Solar Cells Obtained by Aluminium Induced Crystallization and Epitaxy

2009 ◽  
Vol 156-158 ◽  
pp. 413-418 ◽  
Author(s):  
Dries Van Gestel ◽  
Ivan Gordon ◽  
Jef Poortmans
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Solar Cell ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Hydrogen Plasma ◽  
Before And After ◽  
Plasma Passivation ◽  
Conversion Efficiencies ◽  
Induced Crystallization

The relatively new “thin-film polycrystalline-silicon (pc-Si) (grain size of 0.1-100 µm) solar cell on foreign substrate” technology aims at low-cost devices with energy conversion efficiencies above 12 %. A very promising technique to obtain thin pc-Si layers is aluminum-induced crystallization (AIC). Solar cell absorber layers can be made by epitaxial thickening of these AIC seed layers. So far, we have reached energy conversion efficiencies of up to 8% with this approach. In contrast to what is expected a performance independent of the grain size is found which is explained by the presence of intragrain defects. In this paper the electrical activity of both the intragrain defects as well as the grain boundaries is investigated with electron beam induced current (EBIC) measurements before and after hydrogen plasma passivation. Metal-insulator-semiconductor contacts were used as collecting junction to eliminate the interference of the junction shape with the EBIC measurement as found when diffused emitters where used. It is shown that both grain boundaries and intragrain defects are electrically active before and after hydrogen plasma passivation. Finally we argue that Leff,mono, the diffusion length inside the grains, is probably much closer to 1µm in our layers than equal to 100µm as often expected in the literature.

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