Simulation of a Charged Al2O3 Film As An Assisting Passivation Layer For a-Si Passivated Contact p-Type Silicon Solar Cells

2021 ◽  
Author(s):  
Tian Pu ◽  
Honglie Shen ◽  
Quntao Tang
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Potential Application ◽  
High Efficiency ◽  
Defect Density ◽  
Efficiency Gain ◽  
Insulator Layer ◽  
Interface Defect ◽  
P Type ◽  
P Cells

Abstract In this paper, a charged Al2O3 tunneling film as an assisting for amorphous Si (a-Si) passivated contact layer is proposed and theoretically simulated for its potential application in improving a-Si passivated contact p-type (a-PC-p) solar cell. The concept is based on an Ag/n+ c-Si/p c-Si/Al2O3/p+ a-Si/Al structure. The key feature is the introduction of a charged Al2O3 layer, which facilitates the tunneling of holes through an Al2O3 insulator layer accompanied by the reduction of interface defect density (Dit). The negative charge in the Al2O3 layer makes the energy band of p-type c-Si bend upward, realizing the accumulation of holes and repelling of electrons at the c-Si/a-Si interface simultaneously. The influence of interface negative charges (Qit) between a-Si and c-Si, Al2O3 thickness, Al2O3 bandgap, interface defect density (Dit) at the a-Si/c-Si interface are systematically investigated on the output parameters of a-PC-p cells. Inserting a charged Al2O3 film between the c-Si/a-Si interface, a +4.2 % relative efficiency gain is predicted theoretically compared with the a-PC-p cells without the Al2O3 layer. Subsequently, the device performance under various temperatures is simulated, and the insertion of a charged Al2O3 layer obviously decreases the Pmax temperature coefficient from -0.336 % /℃ to -0.247 % /℃, which is analogous to that of Heterojunction with Intrinsic Thin layer (HIT) solar cell. The above results demonstrate a better temperature response for a-PC-p cells with a charged Al2O3 layer, paving a road for its potential application in high-efficiency and high thermal stability a-PC-p solar cells.

17.8%-efficient Amorphous Silicon Heterojunction Solar Cells on p-type Silicon Wafers

2006 ◽  
Vol 910 ◽  
Author(s):  
Qi Wang ◽  
Matt P. Page ◽  
Eugene Iwancizko ◽  
Yueqin Xu ◽  
Yanfa Yan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Short Circuit ◽  
Open Circuit ◽  
Layer Growth ◽  
Surface Recombination Velocity ◽  
Back Contact ◽  
P Type

AbstractWe have achieved an independently-confirmed 17.8% conversion efficiency in a 1-cm2, p-type, float-zone silicon (FZ-Si) based heterojunction solar cell. Both the front emitter and back contact are hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire chemical vapor deposition (HWCVD). This is the highest reported efficiency for a HWCVD silicon heterojunction (SHJ) solar cell. Two main improvements lead to our most recent increases in efficiency: 1) the use of textured Si wafers, and 2) the application of a-Si:H heterojunctions on both sides of the cell. Despite the use of textured c-Si to increase the short-circuit current, we were able to maintain the same 0.65 V open-circuit voltage as on flat c-Si. This is achieved by coating a-Si:H conformally on the c-Si surfaces, including covering the tips of the anisotropically-etched pyramids. A brief atomic H treatment before emitter deposition is not necessary on the textured wafers, though it was helpful in the flat wafers. It is essential to high efficiency SHJ solar cells that the emitter grows abruptly as amorphous silicon, instead of as microcrystalline or epitaxial Si. The contact on each side of the cell comprises a thin (< 5 nm) low substrate temperature (~100°C) intrinsic a-Si:H layer, followed by a doped layer. Our intrinsic layers are deposited at 0.3-1.2 nm/s. The doped emitter and back-contact layers were deposited at a higher temperature (>200°C) and grown from PH3/SiH4/H2 and B2H6/SiH4/H2 doping gas mixtures, respectively. This combination of low (intrinsic) and high (doped layer) growth temperatures was optimized by lifetime and surface recombination velocity measurements. Our rapid efficiency advance suggests that HWCVD may have advantages over plasma-enhanced (PE) CVD in fabrication of high-efficiency heterojunction c-Si cells; there is no need for process optimization to avoid plasma damage to the delicate, high-quality, Si wafers.

The Study of Optical and Electrical Properties of a-SiC:H for Multi-junction Si Thin Film Solar Cell

2010 ◽  
Vol 1245 ◽  
Author(s):  
Jenny H. Shim ◽  
W.K. Yoon ◽  
S.T. Hwang ◽  
S.W. Ahn ◽  
H.M. Lee
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Defect Density ◽  
Wide Bandgap ◽  
Open Circuit ◽  
Deposition Condition ◽  
Wide Bandgap Material ◽  
Pressure Regime

AbstractStudies have shown that wide bandgap material is required for high efficiency multi-junction solar cell applications. Here, we address proper deposition condition for high quality a-SiC:H films. In high power high pressure regime, we observed that the defect density get much lowered to the similar defect level of a-Si:H film with high H2 dilution. Single junction solar cells fabricated with the optimized condition show high open circuit voltage and low LID effect. The degradation after the LID test was only 13 % reduction of the efficiency indicating that a-SiC:H could be promising material for multi-junction solar cells.

Critical Electric Field of InGaN p-i-n Solar Cell

2013 ◽  
Vol 284-287 ◽  
pp. 1168-1172
Author(s):  
Der Yuh Lin ◽  
Chao Yu Chi
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
High Efficiency ◽  
Physical Models ◽  
Electric Field Effect ◽  
Type Layer ◽  
P Type

We present a study of electric field effect on the efficiency of GaN/In0.1Ga0.9N p-i-n solar cells by using the advanced physical models of semiconductor devices (APSYS) simulation program. In this study, the electric field strength and other parameters such as optimum thickness of p-type layer and efficiency of GaN/In0.1Ga0.9N p-i-n solar cells with different i-layer thicknesses have been performed. On the basis of simulating results, for a high efficiency solar cell, it is found that the optimum p-type layer concentration is above 4×1016cm-3and the suitable thickness is between 0.1 to 0.2 μm. For different i-layer thickness and p-doping concentrations, a critical electric field (Fc) has been found at 100 kV/cm. It is worth to note that when the electric field strength of i-layer below Fc value, the solar cell efficiency will dramatically decrease. Thus Fc can be seen as an index for acquiring the quality of solar device.

scholarly journals Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian N. Kruse ◽  
Sören Schäfer ◽  
Felix Haase ◽  
Verena Mertens ◽  
Henning Schulte-Huxel ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Crystalline Silicon ◽  
Silicon Solar Cells ◽  
Efficiency Gain ◽  
Reference Case ◽  
Crystalline Silicon Solar Cells ◽  
Simulation Based ◽  
P Type ◽  
Screen Printed

AbstractWe present a simulation-based study for identifying promising cell structures, which integrate poly-Si on oxide junctions into industrial crystalline silicon solar cells. The simulations use best-case measured input parameters to determine efficiency potentials. We also discuss the main challenges of industrially processing these structures. We find that structures based on p-type wafers in which the phosphorus diffusion is replaced by an n-type poly-Si on oxide junction (POLO) in combination with the conventional screen-printed and fired Al contacts show a high efficiency potential. The efficiency gains in comparsion to the 23.7% efficiency simulated for the PERC reference case are 1.0% for the POLO BJ (back junction) structure and 1.8% for the POLO IBC (interdigitated back contact) structure. The POLO BJ and the POLO IBC cells can be processed with lean process flows, which are built on major steps of the PERC process such as the screen-printed Al contacts and the $$\text{Al}_\text{2 }\text{O}_\text{3 }/\text{SiN }$$ Al 2 O 3 / SiN passivation. Cell concepts with contacts using poly-Si for both polarities ($$\text{POLO}^2$$ POLO 2 -concepts) show an even higher efficiency gain potential of 1.3% for a $$\text{POLO}^2$$ POLO 2 BJ cell and 2.2% for a $$\text{POLO}^2$$ POLO 2 IBC cell in comparison to PERC. For these structures further research on poly-Si structuring and screen-printing on p-type poly-Si is necessary.

High-efficiency, hybrid Si/C60 heterojunction solar cells

2016 ◽  
Vol 4 (42) ◽  
pp. 16410-16417 ◽  
Author(s):  
Myoung Hee Yun ◽  
Jae Won Kim ◽  
Song Yi Park ◽  
Dong Suk Kim ◽  
Bright Walker ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Hybrid Solar Cell ◽  
Organic N ◽  
Heterojunction Solar Cells ◽  
Type Silicon ◽  
Type C ◽  
P Type

The first high-efficiency hybrid solar cell of its type comprising p-type silicon with an organic n-type C60 layer is demonstrated.

III-V Multi-Junction Materials and Solar Cells on Engineered SiGe/Si Substrates

2004 ◽  
Vol 836 ◽  
Author(s):  
Steven A. Ringel ◽  
Carrie L. Andre ◽  
Matthew Lueck ◽  
David Isaacson ◽  
Arthur J. Pitera ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Performance ◽  
High Efficiency ◽  
Defect Density ◽  
Basic Research ◽  
Open Circuit ◽  
Si Substrates ◽  
Lattice Matched ◽  
Open Circuit Voltages

ABSTRACTThe monolithic integration of high efficiency III-V compound solar cell materials and devices with lower-cost, robust and scaleable Si substrates has been a driving force in photovoltaics (PV) basic research for decades. Recent advances in controlling mismatch-induced defects that result from structural and chemical differences between III-V solar cell materials and Si using a combination of SiGe interlayers and monolayer-scale control of III-V/IV interfaces, have led to a series of fundamental advances at the material and device levels, which establish that the great potential of III-V/Si PV is within reach. These include demonstrations of GaAs epitaxial layers on Si that are anti-phase domain-free with verified dislocation densities at or below 1×106 cm−2 and negligible interface diffusion, minority carrier lifetimes for GaAs on Si in excess of 10 ns, single junction GaAs-based solar cells on Si with open circuit voltages (Voc) in excess of 980 mV, efficiencies beyond 18%, and area-independent PV characteristics up to at least 4 cm2. These advances are attributed in large part to the use of a novel “engineered Si substrate” based on compositionally-graded SiGe buffers such that a high-quality, low defect density, relaxed, “virtual” Ge substrate could be developed that can support lattice-matched III-V epitaxy and thus merge III-V technology based on the GaAs (or Ge) lattice constant with Si wafers. This paper focuses on recent results that extend this work to the first demonstration of high performance III-V dual junction solar cells on SiGe/Si. Open circuit voltages in excess of 2 V at one-sun have been obtained for the conventionally “lattice-matched” In0.49Ga0.51P/GaAs dual junction cells on inactive, engineered SiGe/Si; to our knowledge is the first demonstration of > 2V solar power generation on a Si wafer. Comparisons with identical cells on GaAs substrates reveal that the Voc on engineered Si retains more than 94% of its homoepitaxial value, and that at present both DJ/GaAs and DJ/SiGe/Si cells are similarly limited by current mismatch in these early cells, and not fundamental defect factors associated with the engineered Si substrates.

scholarly journals Comprehensive device simulation of 23.36% efficient two-terminal perovskite-PbS CQD tandem solar cell for low-cost applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jaya Madan ◽  
Karanveer Singh ◽  
Rahul Pandey
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Transmission Loss ◽  
Defect Density ◽  
Low Cost ◽  
Solar Spectrum ◽  
Tandem Solar Cell ◽  
Tandem Solar Cells ◽  
Bottom Cell

AbstractThe major losses that limit the efficiency of a single-junction solar cell are thermalization loss and transmission loss. Thus, to efficiently utilize the full solar spectrum and to mitigate these losses, tandem solar cells (TSC) have significantly impacted the photovoltaic (PV) landscape. In this context, the research on perovskite/silicon tandems is currently dominating the research community. The stability improvements of perovskite materials and mature fabrication techniques of silicon have underpinned the rapid progress of perovskite/silicon TSC. However, the low absorption coefficient and high module cost of the silicon are the tailbacks for the mass production of perovskite/silicon TSCs. Therefore, PV technology demands to explore some new materials other than Si to be used as absorber layer in the bottom cell. Thus, here in this work, to mitigate the aforementioned losses and to reduce cost, a 23.36% efficient two-terminal perovskite-PbS CQD monolithic tandem solar cell has been designed through comprehensive device simulations. Before analyzing the performance of the proposed TSC, the performance of perovskite top cells has been optimized in terms of variation in optical properties, thickness, and interface defect density under standalone conditions. Thereafter, filtered spectrum and associated integrated filtered power by the top cell at different perovskite thickness from 50 to 500 nm is obtained to conceive the presence of the top cell above the bottom cell with different perovskite thickness. The current matching by concurrently varying the thickness of both the top and bottom subcell has also been done to obtain the maximum deliverable tandem JSC for the device under consideration. The top/bottom subcell with current matched JSC of 16.68 mA cm−2/16.62 mA cm−2 showed the conversion efficiency of 14.60%/9.07% under tandem configuration with an optimized thickness of 143 nm/470 nm, where the top cell is simulated under AM1.5G spectrum, and bottom cell is exposed to the spectrum filtered by 143 nm thick top cell. Further, the voltages at equal current points are added together to generate tandem J–V characteristics. This work concludes a 23.36% efficient perovskite-PbS CQD tandem design with 1.79 V (VOC), 16.67 mA cm−2 (JSC) and 78.3% (FF). The perovskite-PbS CQD tandem device proposed in this work may pave the way for the development of high-efficiency tandem solar cells for low-cost applications.

scholarly journals Anti-LID Process with a Remote Direct Heating Method Using a Half-Bridge Resonance Circuit for a PERC Solar Cell Module

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 110
Author(s):  
Soo Min Kim ◽  
Sanghoon Jung ◽  
Yoonkap Kim ◽  
Junhee Kim
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Heating Method ◽  
High Efficiency Solar Cells ◽  
P Type ◽  
Cell Module ◽  
Solar Cell Module

As the importance of the levelized cost of electricity (LCOE) increases in the solar cell industry, the demand for high-efficiency solar cells is rapidly increasing. Typically, p-type passivated emitter rear contact (PERC) solar cells are the most commonly used in the industry, and their efficiency is approximately 22–23%. P-type solar cells are reported to exhibit a light-induced degradation (LID) phenomenon, in which their output constantly decreases during power generation under solar radiation, and the output significantly reduces as their reference efficiency increases. Ultra-high-efficiency solar cells, which are on high demand, have a considerable output reduction due to the LID phenomenon; hence, technologies to prevent the LID phenomenon are required. However, research on this phenomenon has not been conducted because there is no method to transfer heat to solar cells inside the encapsulant when the modules are produced. In this study, a regeneration state was formed by remotely heating solar cells without damaging the encapsulant of the solar cell module. This was accomplished by using a heating method based on an induction magnetic field. A half-bridge resonance circuit was used to apply the induction magnetic field, and the temperature of the solar cell was controlled by adjusting the magnitude of the current flowing through the coil. To determine whether only the solar cell was heated, the temperature distribution inside the module was analyzed using an IR camera. The minority carrier lifetime was examined by real-time observation of the open-circuit voltage pattern of the solar cell. Finally, the observed real-time open-circuit voltage data were used, and dynamic simulation of the regeneration process was applied to analyze the LID activation energy generated in the regeneration process of the solar cell module. In conclusion, research was conducted on applying the regeneration state to prevent the LID phenomenon in the solar-cell-module stage, and the LID activation energy of the solar cell module was extracted. Based on this, a nondestructive degradation prevention technology for the solar cell module was developed.

scholarly journals Numerical Simulation Analysis of Ag Crystallite Effects on Interface of Front Metal and Silicon in the PERC Solar Cell

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 592
Author(s):  
Myeong Sang Jeong ◽  
Yonghwan Lee ◽  
Ka-Hyun Kim ◽  
Sungjin Choi ◽  
Min Gu Kang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Surface Recombination ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Metal Interface ◽  
Ag Crystallites ◽  
Recombination Velocity

In the fabrication of crystalline silicon solar cells, the contact properties between the front metal electrode and silicon are one of the most important parameters for achieving high-efficiency, as it is an integral element in the formation of solar cell electrodes. This entails an increase in the surface recombination velocity and a drop in the open-circuit voltage of the solar cell; hence, controlling the recombination velocity at the metal-silicon interface becomes a critical factor in the process. In this study, the distribution of Ag crystallites formed on the silicon-metal interface, the surface recombination velocity in the silicon-metal interface and the resulting changes in the performance of the Passivated Emitter and Rear Contact (PERC) solar cells were analyzed by controlling the firing temperature. The Ag crystallite distribution gradually increased corresponding to a firing temperature increase from 850 ∘C to 950 ∘C. The surface recombination velocity at the silicon-metal interface increased from 353 to 599 cm/s and the open-circuit voltage of the PERC solar cell decreased from 659.7 to 647 mV. Technology Computer-Aided Design (TCAD) simulation was used for detailed analysis on the effect of the surface recombination velocity at the silicon-metal interface on the PERC solar cell performance. Simulations showed that the increase in the distribution of Ag crystallites and surface recombination velocity at the silicon-metal interface played an important role in the decrease of open-circuit voltage of the PERC solar cell at temperatures of 850–900 ∘C, whereas the damage caused by the emitter over fire was determined as the main cause of the voltage drop at 950 ∘C. These results are expected to serve as a steppingstone for further research on improvement in the silicon-metal interface properties of silicon-based solar cells and investigation on high-efficiency solar cells.

Improvement in Wide-Gap A-SI:H For High-Efficiency Solar Cells

1992 ◽  
Vol 258 ◽  
Author(s):  
Sadaji Tsuge ◽  
Yoshihiro Hishikawa ◽  
Shingo Okamoto ◽  
Manabu Sasaki ◽  
Shinya Tsuda ◽  
...  
Keyword(s):  
Solar Cells ◽  
Plasma Treatment ◽  
High Efficiency ◽  
Defect Density ◽  
Hydrogen Plasma ◽  
Wide Band ◽  
Open Circuit ◽  
Wide Band Gap ◽  
High Efficiency Solar Cells ◽  
Wide Gap

ABSTRACTA hydrogen-plasma treatment has been used for the first time to fabricate wide-gap, high-quality a-Si:H films. The hydrogen content (CH) of a-Si:H films substantially increases by the hydrogen-plasma treatment after deposition, without deteriorating the opto-electric properties of the films. The photoconductivity (σph) of ≥ 10-5 ο-1 cm-1, photosensitivity ( σ ph/σ d) of > 106 and SiH2/SiH of <0.2 are achieved for a film with CH of ∼25 atomic >%. The optical gap of the film is > 1.70 eV by the (α h ν )1/3 plot, and is >2 eV by the Tauc's plot. The open circuit voltage of a-Si solar cells exceeds 1 V conserving the fill factor of > 0.7 when the wide-gap a∼Si:H films are used as the i-layer, which proves the wide band gap and low defect density.

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