Improved silicon oxide/polysilicon passivated contacts for high efficiency solar cells via optimized tunnel layer annealing

Kaur, Gurleen; Zhang, Xin; Dutta, Tanmay; Sridharan, Ranjani; Stangl, Rolf; Danner, Aaron J.

doi:10.1016/j.solmat.2020.110720

Cited by 16 publications

(9 citation statements)

References 32 publications

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“…For n‐type poly‐Si contacts, the absorption peaks located at ~890 cm −1 (SiH bond) 32,33 and ~970 cm −1 (SiOH bond) 34,35 slightly increased in intensity after firing, while the height of the peaks at 2330 to 2360 cm −1 (SiH x [ x = 1, 2, 3] bonds) increased substantially 36,37 . It is also noted that peak intensity of the SiOSi bonds detected at 1120 cm −1 was unchanged upon firing, 38–40 suggesting that the stoichiometry of the interfacial SiO x layers were not significantly altered by the 800°C firing treatment 37,41 . In contrast to n‐type poly‐Si, p‐type poly‐Si/SiO x passivating contacts showed nearly identical FTIR spectra before and after firing.…”

Section: Resultsmentioning

confidence: 96%

“…36,37 It is also noted that peak intensity of the Si O Si bonds detected at 1120 cm À1 was unchanged upon firing, [38][39][40] suggesting that the stoichiometry of the interfacial SiO x layers were not significantly altered by the 800 C firing treatment. 37,41 In contrast to n-type poly-Si, p-type poly-Si/SiO x passivating contacts showed nearly identical FTIR spectra before and after firing. The distinct FTIR results for n-and p-type poly-Si contacts yield information about the different molecular interactions occurring during the firing process.…”

Section: Impact Of Firing Temperature On N-and P-type Poly-simentioning

confidence: 99%

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Comparison of firing stability between p‐ and n‐type polysilicon passivating contacts

Kang

Sio

Stückelberger

et al. 2022

Progress in Photovoltaics

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This work compares the firing response of ex‐situ doped p‐ and n‐type polysilicon (poly‐Si) passivating contacts and identifies possible mechanisms underlying their distinct firing behavior. The p‐type poly‐Si shows greater firing stability than n‐type poly‐Si, particularly at a higher firing temperature, which results in a substantial increase in the recombination current density parameter J0 from 9 to 96 fA/cm2 upon firing at 900°C for n‐type poly‐Si, in comparison to an increase from 11 to 30 fA/cm2 for p‐type poly‐Si. It is observed that p‐type poly‐Si contacts only suffer a slight degradation or even exhibit a small improvement in J0 after firing at 800°C, depending on the boron diffusion temperature. Secondary ion mass spectrometry (SIMS) results demonstrate that the hydrogen concentration near the interfacial SiOx increases with the peak firing temperature in n‐type poly‐Si, whereas the hydrogen profile remains unchanged for p‐type poly‐Si upon firing at various temperatures. Moreover, we observe that injecting additional hydrogen into the poly‐Si/SiOx stacks fired with SiNx coating layers further degrades n‐type poly‐Si, but recovers the J0 of p‐type poly‐Si to the value before firing. In contrast, removing hydrogen from the fired poly‐Si/SiOx stacks leads to an initial recovery and then a second degradation of J0 in n‐type poly‐Si, but no substantial impact on p‐type poly‐Si. It is hypothesized that the distinct difference in the firing impact on p‐ and n‐type poly‐Si is related to the different effective hydrogen diffusivity, which determines the hydrogen content surrounding the SiOx layer and hence the passivation quality after firing.

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Section: Resultsmentioning

confidence: 96%

Section: Impact Of Firing Temperature On N-and P-type Poly-simentioning

confidence: 99%

Comparison of firing stability between p‐ and n‐type polysilicon passivating contacts

Kang

Sio

Stückelberger

et al. 2022

Progress in Photovoltaics

View full text Add to dashboard Cite

show abstract

“…To figure out the time dependence of the effect of CIA treatment, several sets of TOPCon solar cells (Group II) were selected to perform the CIA treatment at 320 C with 13 A current injection with different duration (10,20,40,80, and 120 min), the changes in η, FF, V oc , I sc before and after the CIA treatment are presented in Figure 2. It is clear that all the electrical parameters of these cells are improved after the CIA treatment.…”

Section: Resultsmentioning

confidence: 99%

“…Notably, the conversion efficiency of TOPCon solar cells has been improved a lot recently, due to plenty of efforts focused on the tunnel oxide, interface, work function, annealing, and post-treatments. [6][7][8][9][10][11] However, there are still some important and difficult problems which limit further increasing in the electrical performance need to be solved for improving the efficiency of TOPCon solar cells. One of the most important issues is the recombination at the contacts and the interfaces.…”

Section: Introductionmentioning

confidence: 99%

Carrier Injection and Annealing‐Enhanced Electrical Performance in Tunnel Oxide‐Passivated Contact Silicon Solar Cells

Song

Lin

et al. 2021

Physica Status Solidi (a)

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Herein, it is demonstrated that low temperature current injection and annealing (CIA) treatment can cause evident improvements in open circuit voltage, short‐circuit current, and fill factor of tunnel oxide‐passivated contact (TOPCon) silicon solar cells, leading to a notable conversion efficiency gain (over 0.4% absolute at the best condition). The effects of injected current and annealing temperatures toward the improvement of electrical performance of the TOPCon solar cells are compared. The more evident increase in the electrical performance after the CIA treatment may come from the higher fill factor improvements, which can be induced by the change of contact resistance after the CIA treatment, the potential involvement of hydrogen is discussed. The CIA treatment can be a reliable approach to further enhance the conversion efficiency of TOPCon solar cells, which is of great significance for the global PV industry.

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“…Above all, SiO x as an insulator, when the thickness is too thin, the chemical passivation effect is not obvious, and when it is too thick, the chance of carrier tunneling decreases, thus affecting the passivation effect, and when the thickness reaches several tens of nanometers, it becomes a complete insulator so that carriers cannot pass through. [22,23] Ideally, a 1.5-2 nm oxide layer is desirable in the experiments to obtain the best chemical passivation, which explains why some oxidation methods where the oxide layer thickness is not easily controlled do not give excellent passivation results. The generation of oxide layer pinholes is related to the oxidation process.…”

Section: Effects Of Detailed Parameters On Device Performancesmentioning

confidence: 99%

Computational Exploration Toward Tunnel Oxide Passivated Contact (TOPCon) Solar Cells: Tailoring Higher Efficiency

Zhou

Ren

et al. 2022

Advcd Theory and Sims

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Despite the inescapable technical challenges and unclear operating mechanisms, the last few years have witnessed considerable advances in tunnel oxide passivated contact (TOPCon) structured solar cells, most of which are centered around improving the device performance so as to truly become a step forward from current mainstream technologies. However, a systematic numerical exploration is urgently required to gain a thorough understanding of the effect of the core parameters of the device on the final performance. Here, the numerical simulation way is used to explore the potential of TOPCon technology, focused on the pursuit of higher efficiency. An exhaustive analysis concerning tunnel SiOx and doped polysilicon (poly‐Si) with field passivation effect is carried out to tailor excellent surface passivation. The simulation also suggests that the ultra‐thin SiOx with extremely low pinhole density can suppress the recombination of carriers, thus promoting the passivation quality. Additionally, simulation research is conducted on the potential of using poly‐SiOx(n+) as the doped layer, and an efficiency of 27.60% is realized via adjusting the optimal band gap and dopant concentration. Briefly, this work presents a comprehensive computational analysis of the tunnel oxide, doped layer and their synergistic impacts on the final performance.

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Improved silicon oxide/polysilicon passivated contacts for high efficiency solar cells via optimized tunnel layer annealing

Cited by 16 publications

References 32 publications

Comparison of firing stability between p‐ and n‐type polysilicon passivating contacts

Comparison of firing stability between p‐ and n‐type polysilicon passivating contacts

Carrier Injection and Annealing‐Enhanced Electrical Performance in Tunnel Oxide‐Passivated Contact Silicon Solar Cells

Computational Exploration Toward Tunnel Oxide Passivated Contact (TOPCon) Solar Cells: Tailoring Higher Efficiency

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