Hydrogen-Assisted Defect Engineering of Doped Poly-Si Films for Passivating Contact Solar Cells

Journal Article · 25 November 2019 · ACS Applied Energy Materials

DOI: https://doi.org/10.1021/acsaem.9b01771 · OSTI ID:1579320

Truong, Thien N.  ^[1]; Yan, Di ^[1]; Samundsett, Christian ^[1]; Liu, Anyao  ^[1]; Harvey, Steven P.  ^[2]; Young, Matthew ^[2]; Ding, Zetao ^[1]; Tebyetekerwa, Mike  ^[1]; Kremer, Felipe ^[1]; Al-Jassim, Mowafak ^[2]; Cuevas, Andres ^[1]; Macdonald, Daniel ^[1]; Nguyen, Hieu T.  ^[1]

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1. Australian National Univ., Canberra, ACT (Australia)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Hydrogen-assisted defect engineering, via a hydrogenated silicon nitride (SiN_x:H) capping layer, on doped polycrystalline silicon (poly-Si) passivating-contact structures, is explored using complementary techniques. The hydrogen treatment universally improves the passivation quality of poly-Si/SiO_x stacks on all samples investigated. Meanwhile, their contact resistivity remains very low at ~6 m$$\Omega$$cm². Moreover, the nature of charge carrier recombination within the poly-Si films is also investigated by means of photoluminescence. On planar c-Si substrates, the poly-Si films emit two broad photoluminescence peaks ~850-1050 nm and ~1300-1500 nm. The former is the characteristic peak of the hydrogenated amorphous Si (a-Si:H) phase and only appears after the treatment, demonstrating that i) a significant amount of hydrogen has been driven into the poly-Si film and ii) an amorphous phase is present within it. The second peak originates from sub-bandgap radiative defects inside the poly-Si films and increases after the treatment, suggesting a suppression of their non-radiative recombination channels. For films deposited on textured c-Si substrates, there is a disrupted oxide boundary, preventing a build-up of excess carriers inside the films and leading to quenching of the film luminescence.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); Australian Renewable Energy Agency (ARENA); Australian Centre for Advanced Photovoltaics (ACAP); Australian Government Research Training Program (RTP)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1579320
• Report Number(s): NREL/JA-5K00-74683
• Journal Information: ACS Applied Energy Materials, Journal Name: ACS Applied Energy Materials Journal Issue: 12 Vol. 2; ISSN 2574-0962
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English