scholarly journals Electro-Optical Characteristics of Shallow Silicon Junctions Fabricated Through Masked Ion Implantation

1985 ◽  
Vol 45 ◽  
Author(s):  
Andrei P. Silard
Keyword(s):  
Ion Implantation ◽  
Spectral Response ◽  
Short Circuit ◽  
Visible Spectrum ◽  
Short Circuit Current ◽  
Oxide Thickness ◽  
Short Circuit Current Density ◽  
Optical Characteristics ◽  
Technological Parameters ◽  
Large Bandwidth

ABSTRACTThe work presents the main electro-optical characteristics of very shallow silicon n+-p and P+-n junctions fabricated through masked ion implantation of phosphorus (31P+) and boron (11B+), respectively. The dependence of electro-optical characteristics on technological parameters (implant energy E and dose Q, oxide thickness Xox, impurity redistributions, etc.) are outlined in detail.The implant step was performed through a thermally-grown silicon dioxide (SiO2) mask of variable thickness (Xox = 100-1200 Å) at energies ranging from E=10 keV to 50 keV and with a dose level Q = 5 x 1014 - 2 x 1015 cm-2. As a rule, after the implant step the oxide layer was etched down. In several samples, the Si0 2 layer was preserved in the finished devices.The characterization of fabricated junctions was performed using a Karl Zeiss quartz prism monochromator coupled to a Tektronix 31/4661 data acquisition system. The main peculiar results could be summarized as follows: (a) all fabricated devices possess a relatively large bandwidth (up to 580 nm) of the relative spectral response; (b) for oxide thickness Xox Rp (projected range), the low energy implant yields devices with good blue response; (c) for Xox equal or larger than Rp a pronounced shift of the peak responsivity wavelength toward the visible spectrum of the light occurs; (d) a distinctive feature of devices consists in the high peak values of the short-circuit current density under AM1 insolation (in excess of 33 mA/cm2); (e) the preservation of SiO2 layer in the finished devices improves their electro-optical characteristics.

Solar Cells on Foreign Substrates Using Poly-Si Thin Films by Metal Induced Growth

2004 ◽  
Vol 808 ◽  
Author(s):  
Chunhai Ji ◽  
Wayne A. Anderson
Keyword(s):  
Solar Cells ◽  
Ion Implantation ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Doping Density ◽  
Charge Densities ◽  
Metal Induced Growth

ABSTRACTThe poly-Si film was deposited by using the metal-induced growth (MIG) method on tungsten substrates. By making Au/n-Si Schottky photo-diodes, doping density effect was studied by using three different doping level Si sputtering targets. Increasing the Si target resistivities from 0.02Ω-cm to 50Ω-cm, open-circuit-voltage (Voc) decreased from 0.22V to 0.14V while short-circuit-current density (Jsc) increased from 1.55mA/cm2 to 2.42mA/cm2. C-V results revealed a high charge density in the device, which may be due to the oxygen thermal donor effects. Using an oxygen filter for the sputtering gas effectively reduced the charge densities and increased the Jsc value. The p/n junction solar cells were fabricated by using ion implantation at 1013∼1014cm−2 dose and 100∼200keV. The cells with wider emitter layer by double-ion implantation gave higher Jsc and Voc values. Passivation of the Si film by using hydrogenation improved the Jsc, Voc and spectral response of the solar cells.

Design and modeling of an SJ infrared solar cell approaching upper limit of theoretical efficiency

2018 ◽  
Vol 32 (02) ◽  
pp. 1850014 ◽  
Author(s):  
G. S. Sahoo ◽  
G. P. Mishra
Keyword(s):  
Solar Cell ◽  
Quantum Efficiency ◽  
Conversion Efficiency ◽  
Internal Quantum Efficiency ◽  
Spectral Response ◽  
Short Circuit ◽  
Cost Effective ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit

Recent trends of photovoltaics account for the conversion efficiency limit making them more cost effective. To achieve this we have to leave the golden era of silicon cell and make a path towards III–V compound semiconductor groups to take advantages like bandgap engineering by alloying these compounds. In this work we have used a low bandgap GaSb material and designed a single junction (SJ) cell with a conversion efficiency of 32.98%. SILVACO ATLAS TCAD simulator has been used to simulate the proposed model using both Ray Tracing and Transfer Matrix Method (under 1 sun and 1000 sun of AM1.5G spectrum). A detailed analyses of photogeneration rate, spectral response, potential developed, external quantum efficiency (EQE), internal quantum efficiency (IQE), short-circuit current density (J[Formula: see text]), open-circuit voltage (V[Formula: see text]), fill factor (FF) and conversion efficiency ([Formula: see text]) are discussed. The obtained results are compared with previously reported SJ solar cell reports.

Enhanced Light Absorption in a-Si:H Layers of Solar Cells by Applying Tco/Metal Back Contacts

1993 ◽  
Vol 297 ◽  
Author(s):  
G. Tao ◽  
B.S. Girwar ◽  
G.E.N. Landweer ◽  
M. Zeman ◽  
J.W. Metselaar
Keyword(s):  
Solar Cells ◽  
Metal Layer ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Back Contact ◽  
Flat Substrate ◽  
Metal Layers ◽  
Metal Back

The optimization of the back contact reflectivity for thin film a-Si:H solar cells has been performed. The results of optical calculations show that a-Si:H/TCO/Metal interfaces with a proper TCO thickness reflect much more than their a-Si:H/Metal counterparts. We compared solar cells which were deposited on a flat substrate with different back contacts. The back contacts consisted of a metal layer (aluminum, silver/aluminum) or combined TCO/metal layers (TCO/Al, TCO/Ag/Al). The same was done with solar cells which were deposited on a textured substrate. The solar cells with a TCO/metal back contact showed not only a significantly increased short-circuit current density but also an increase in the spectral response. The cells with TCO/Ag/Al back contact showed the best result.

Effect of CdCl2 Treatment of CdS Films on CdTe/CdS Solar Cells

1996 ◽  
Vol 426 ◽  
Author(s):  
W. Song ◽  
D. Mao ◽  
L. Feng ◽  
Y. Zhu ◽  
M. H. Aslan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
X Ray Diffraction ◽  
Cdcl2 Treatment ◽  
The Difference ◽  
Cds Films

AbstractWe investigated the effect of CdCl2 treatment of CdS films on the photovoltaic performance of polycrystalline CdTe/CdS solar cells. X-ray diffraction studies indicated that the diffusion of S into CdTe is qualitatively the same for CdTe/CdS films fabricated with both as-deposited and CdCl2-treated CdS. A major difference was observed in the extent of Te diffusion into CdS for the two types of CdS films. Full conversion of CdS into CdS1-yTey; was observed for films prepared with asdeposited CdS, while the formation of the ternary phase was below the detection limit for films prepared with CdCl2-treated CdS. Photoluminescence measurements confirmed this result. The difference in interdiffusion leads to differences in optical transmission of CdS films and spectral response of CdTe/CdS solar cells. An increase of 2.7 mA/cm2 in short-circuit current density was observed as a result of improved spectral response in the wavelength range of 500–600 nm for the CdCl2-treated CdS.

Photogeneration and Carrier Transport in Amorphous Silicon/Crystalline Silicon Devices

1997 ◽  
Vol 467 ◽  
Author(s):  
B. Jagannathan ◽  
W. A. Anderson
Keyword(s):  
Amorphous Silicon ◽  
Carrier Transport ◽  
Crystalline Silicon ◽  
Plasma Deposition ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Silicon Devices

ABSTRACTHydrogenated amorphous silicon (a-Si:H)/ crystalline silicon (c-Si) type heterodiodes in solar cell structures have been studied by rf glow discharge, dc magnetron sputtering, and a remote plasma deposition of a-Si:H onto p type c-Si. Carrier transport and photogeneration in such structures have been investigated by current-voltage-temperature, thermally stimulated capacitance (TSCAP), and spectral response experiments. Dark carrier conduction is found to be a combination of tunneling and interface recombination, but is dominated by either one depending on the deposition/sputtering conditions. The conditions investigated include energy of the plasma species, type of plasma cleaning, and substrate preparation techniques. For each of the conditions, the trap type, energy and concentration have been identified by TSCAP. Solar cells fabricated by the optimized fabrication scheme routinely yield 10.5% efficient devices having a short circuit current density (Jsc) of 30 mA/cm2, a open circuit voltage of 0.55 volts and a fill factor (FF) of 0.64, without an AR coating, over 0.3 cm2 area.

Preparation of Narrow-gap a-Si:H Solar Cells by VHF-PECVD Technique

2010 ◽  
Vol 1245 ◽  
Author(s):  
Do Yun Kim ◽  
Ihsanul Afdi Yunaz ◽  
Shunsuke Kasashima ◽  
Shinsuke Miyajima ◽  
Makoto Konagai
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Hydrogen Flow ◽  
Long Wavelength

AbstractOptical, electrical and structural properties of silicon films depending on hydrogen flow rate (RH), substrate temperature (TS), and deposition pressure (PD) were investigated. By decreasing RH and increasing TS and PD, the optical band gap (Eopt) of silicon thin films drastically declined from 1.8 to 1.63 eV without a big deterioration in electrical properties. We employed all the investigated Si thin films for p-i-n structured solar cells as absorbers with i-layer thickness of 300 nm. From the measurement of solar cell performances, it was clearly observed that spectral response in long wavelength was enhanced as Eopt of absorber layers decreased. Using the solar cell whose Eopt of i-layer was 1.65 eV, the highest QE at long wavelength with the short circuit current density (Jsc) of 16.34 mA/cm2 was achieved, and open circuit voltage (Voc), fill factor (FF), and conversion efficiency (η) were 0.66 V, 0.57, and 6.13%, respectively.

Amorphous Crystalline Silicon Heterojunction with Silicon Nitride Buffer Layer

2000 ◽  
Vol 609 ◽  
Author(s):  
G. Claudio ◽  
R. De Rosa ◽  
F. Roca ◽  
D. Caputo ◽  
M. Tucci
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Buffer Layer ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Wavelength Region ◽  
Visible Spectrum ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Deposition Parameters

ABSTRACTIn this work we study the possibility to use amorphous silicon nitride, grown by plasma, as an alternative way to realize buffer layer in a-Si:H/c-Si heterostructure. We experimented several growing condition for silicon nitride depending on deposition parameters, obtaining samples highly transparent and with optical gap varying in the range 2.4 – 5.2 eV. We found evidence that the gap of the material is principally due to the NH3/N2 ratio. The very low absorption obtainable on this material was successfully utilized to increase the short circuit current density of the device respect to the standard cell with intrinsic amorphous silicon buffer, particularly in the low wavelength region as confirmed by quantum yield measurements. We optimized the thickness of the SiNx buffer layer respect to the photovoltaic parameters of the solar cell. A 0.5 nm thick SiNx ensures good photogeneration in blue region of the visible spectrum and does not appreciably degrade the transport mechanism of the heterojunction.

Two-Dimensional Modelling and Simulation of Crystalline Silicon n+pp+ Solar Cell

2012 ◽  
Vol 260-261 ◽  
pp. 154-162
Author(s):  
S. Tobbeche ◽  
M.N. Kateb
Keyword(s):  
Solar Cell ◽  
Open Circuit Voltage ◽  
Crystalline Silicon ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
The Other ◽  
Electrical Characteristics

In this work, we present the simulation results of the technological parameters and the electrical characteristics of a crystalline silicon n+pp+ solar cell, using two-dimension (2D) software, namely TCAD Silvaco (Technology Computer Aided Design). TCAD Silvaco Athena is used to simulate various stages of the technology manufacturing, while TCAD Silvaco Atlas is used for the simulation of the electrical characteristics and the spectral response of the solar cell. The J-V characteristics and the external quantum efficiency (EQE) are simulated under AM 1.5 illumination. The conversion efficiency(η)of 16.06% is reached and the other characteristic parameters are simulated: the open circuit voltage (Voc) is of 0.63 V, the short circuit current density (Jsc) equals 30.54 mA/cm² and the form factor (FF) is of 0.83 for the n+pp+ solar cell with a silicon nitride antireflection layer (Si3N4). In order to highlight the importance of the back surface field (BSF), a comparison between two cells, one without BSF (structure n+p), the other with one BSF (structure n+pp+), was made. By creating a BSF on the rear face of the cell the short circuit current density increases from 28.55 to 30.54 mA/cm2, the open circuit voltage from 0.6 to 0.63 V and the conversion efficiency from 14.19 to 16.06%. A clear improvement of the spectral response is obtained in wavelengths ranging from 0.65 to 1.1 µm for the solar cell with BSF.

Light Trapping in Thin-film μc-Si:H Solar Cells using Self-ordered 2D Grating Reflector

2009 ◽  
Vol 1153 ◽  
Author(s):  
Hitoshi Sai ◽  
Yoshiaki Kanamori ◽  
Michio Kondo
Keyword(s):  
Light Scattering ◽  
Near Infrared ◽  
Light Trapping ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Infrared Region ◽  
Short Circuit Current Density ◽  
Rear Side ◽  
Patterned Substrates

AbstractEffect of back reflectors on light trapping in μc-Si:H cells has been investigated with self-ordered Al substrates obtained by anodic oxidation. With increasing the period of the patterned substrates from 0 to 1.1 μm, 1-μm-thick μc-Si:H cells on the patterned substrates have shown a significant enhancement of spectral response in the near infrared region, giving an increment of the short circuit current density from 18 to 24 mA/cm2. This enhanced light trapping effect are attributed to the improved reflectivity of the rear side and effective light scattering at the front side, as well as light scattering at the rear side.

A Novel Solar Cell Shallow Emitter Formation Process by Ion-Implantation and Dopant Modulation Through Surface Chemical Etching

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Wei-Lin Yang ◽  
Po-Hung Chen ◽  
Kun-Rui Wu ◽  
Likarn Wang
Keyword(s):  
Ion Implantation ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Advanced Technology ◽  
Surface Chemical ◽  
Recombination Rates ◽  
Selective Emitter ◽  
Novel Method ◽  
Wet Etch

Ion-implantation is an advanced technology to inject dopants for shallow junction formation. Due to the ion-induced sputtering effect at low implant energy where dopants tend to accumulate at the silicon surface, the excess ion doses can be easily removed via a surface chemical wet etching process. By taking advantage of the dose limitation characteristic, we proposed a novel method to form shallow emitters with various dopant densities. Two integration flows have been investigated: (1) wet etch after implantation before junction anneal and (2) wet etch after implantation and junction anneal. The two integration flows observed a difference in the density of doping impurities during the thermal process, which is related to the substrate recombination rates. Selective emitter (SE) structures with the two types of integration flows were characterized. Comparing the blanket emitter and SE structures with two types of etching methods, the device with wet etch before annealing process achieved the best effective carrier lifetime of 53.05 μs, which leads to a higher short circuit current density. Hence, this SE cell demonstrated a better blue response and shows an improvement in the conversion efficiency.

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