Gettering of impurities in solar silicon

Perichaud, I.

doi:10.1016/s0927-0248(01)00179-9

Cited by 78 publications

(27 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sources of iron, its distribution in the forms of Fe i and Fe precipitates, and Fe gettering effects [30]- [32] during the solar cell manufacturing processes are well investigated. The iron contamination mainly comes from the quartz crucible and the silicon nitride coating of the latter used for the Si ingot production [33]- [36].…”

mentioning

confidence: 99%

Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Bauer

Hähnel

Werner

et al. 2016

IEEE J. Photovoltaics

View full text Add to dashboard Cite

Abstract-Lomer dislocations at small-angle grain boundaries in multicrystalline silicon solar cells have been identified as responsible for the dominating inherent dark current losses. Resulting efficiency losses have been quantified by dark lock-in thermography to be locally up to several percent absolute, reducing the maximum power of the cells. By electron beam induced current measurements and scanning transmission electron microscopy investigations, it is revealed that the strengths of the dark current losses depend on the density of Lomer dislocations at the small-angle grain boundaries.

show abstract

mentioning

confidence: 99%

Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Bauer

Hähnel

Werner

et al. 2016

IEEE J. Photovoltaics

View full text Add to dashboard Cite

show abstract

“…• C for 20 min, these values increase substantially, due to a slight gettering effect which removes impurities which can be easily extracted from the bulk [8]. Figures 1 and 2 show the variations of the mean values of L dif and τ dif as a function of the position along the ingot height and also those of L get and τ get measured after gettering by phosphorus diffusion at 900…”

Section: Resultsmentioning

confidence: 99%

Minority carrier bulk lifetimes through a large multicrystalline silicon ingot and related solar cell properties

Martinuzzi

Gauthier²,

Barakel

et al. 2007

Eur. Phys. J. Appl. Phys.

View full text Add to dashboard Cite

Abstract. The bulk lifetime τn and diffusion length Ln of minority carriers vary through the height of a cast multicrystalline silicon (mc-Si) block. This variation is due to the segregation of metallic impurities during the directional solidification and the native impurity concentrations increase from the bottom to the top of the ingot, which is solidified last, while the ingot bottom, which is solidified first, is contaminated by the contact with the crucible floor. It is of interest to verify if a correlation exists between the bulk lifetime τ of as cut wafers and the conversion efficiency η of solar cells. In a very large ingot (>310 kg), it was found that τ0, in raw wafers, τ dif in phosphorus diffused ones and Ln in diffused wafers are smaller in the top and in the bottom of the ingot. The same evolution is observed in solar cells, however the diffusion length values L cel in the central part of the ingot are markedly higher than those found in diffused wafers, due to the in-diffusion of hydrogen from the SiN-H antireflection coating layer. The variations of η and those of τ0, along the ingot height, are well correlated, suggesting that the evaluation of τ0 can predict the properties of the devices. In addition, segregation phenomena around the grain boundaries are observed at the bottom of the ingots, due to a marked contamination by the crucible floor, and at its top where impurities are accumulated. These phenomena are linked to the long duration of the solidification process and the large amount of imperfect silicon used to cast the ingot.

show abstract

“…A previous study reported that a PSG layer can serve as a gettering layer because of the differences in the segregation coefficient between a PSG layer and Si substrate. 20 This could explain the high concentration of Na ions at the SixNy/PSG interface. In the present study, the PSG layer played a crucial role in reducing the PID.…”

Section: Resultsmentioning

confidence: 99%

A Well-Controlled PSG Layer on Silicon Solar Cells against Potential Induced Degradation

Chen

et al. 2015

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

This study proposes a promising silicon (Si) solar cell structure for reducing the potential induced degradation (PID) of crystalline Si solar cells. Phosphorous silicate glass (PSG) layers were carefully designed on an emitter layer, and the thickness of these layers (d PSG ) was controlled by adjusting the diffusion temperature and time. The results show that the power loss remarkably decreased from 31% (d PSG = 0 nm) to 11% (d PSG = 22.3 nm) and further decreased to less than 5% after a 48-h PID test when d PSG In recent years, the number of large photovoltaic (PV) systems for generating high electricity has increased. Such PV systems contain numerous high power PV modules. Therefore, the durability of a PV module is imperative.1 The potential induced degradation (PID) of crystalline silicon (Si) solar cells, first observed by Sunpower in 2005, has drawn considerable attention in recent years. [2][3][4][5][6] This is because the local electrical short-circuiting of the pn-junction in a Si solar cell occurs under high voltage stress, which leads to a substantial reduction in the power of a module. 7Several approaches can be used to prevent PID from cell to module levels. For example, leakage current can be reduced by changing the cover glass and encapsulation materials. [8][9][10] However, applying these approaches increases the cost drastically and may cause the efficiency of solar cells to deteriorate. The soda-lime cover glass and ethylene vinyl acetate (EVA) are still the most widely used and low-cost packaging materials for solar modules. Strong demand has necessitated the modification of the antireflective layers or emitter layers in PID-resistant solar cells. However, risks should be noticed that an efficiency of a solar cell and throughput may be reduced.This study proposes a promising Si solar cell structure for reducing the PID of solar cells without influencing their efficiency and throughput. Phosphorous silicate glass (PSG) layers were carefully designed on an emitter layer to determine how they affect the efficiencies of solar cells before and after PID. A current-voltage (I-V) tester was used to determine PV parameters. An ellipseometer and transmission electron microscope (TEM) were used to measure the thicknesses of the PSG layers. Secondary ion mass spectrometry (SIMS) was used to obtain concentration profiles of Si, sodium (Na), phosphorus (P), oxygen, and nitrogen. Figure 1 shows the process flow in this study as well as the structure of a solar cell with a PSG layer. Solar-grade and monocrystalline Si wafers with a size and resistivity of 5 in 2 and 0.5-3.0 ·cm, respectively, were used in this study. These wafers were processed using the following procedures: texturization by using an alkaline solution, P diffusion by using POCl 3 as a precursor, removing PSG layers by using a dilute HF solution (for standard solar cells only), depositing SixNy films as antireflection coatings by using a plasma enhanced chemical vapor deposition, and forming front and rear contacts by performing screen-p...

show abstract

Gettering of impurities in solar silicon

Cited by 78 publications

References 21 publications

Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Minority carrier bulk lifetimes through a large multicrystalline silicon ingot and related solar cell properties

A Well-Controlled PSG Layer on Silicon Solar Cells against Potential Induced Degradation

Contact Info

Product

Resources

About