Influence of CdTe Deposition Temperature and Window Thickness on CdTe Grain Size and Lifetime After CdCl₂ Recrystallization

Journal Article · 23 January 2018 · IEEE Journal of Photovoltaics

DOI: https://doi.org/10.1109/JPHOTOV.2018.2790701 · OSTI ID:1422693

Amarasinghe, Mahisha  ^[1]; Colegrove, Eric  ^[2]; Moutinho, Helio ^[2]; Albin, David ^[2]; Duenow, Joel  ^[2]; Johnston, Steve ^[2]; Kephart, Jason ^[3]; Sampath, Walajabad ^[3]; Al-Jassim, Mowafak ^[2]; Sivananthan, Siva ^[1]; Metzger, Wyatt K. ^[2]

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1. Univ. of Illinois, Chicago, IL (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
3. Colorado School of Mines, Golden, CO (United States)

Grain structure influences both transport and recombination in CdTe solar cells. Larger grains generally are obtained with higher deposition temperatures, but commercially it is important to avoid softening soda-lime glass. Furthermore, depositing at lower temperatures can enable different substrates and reduced cost in the future. We examine how initial deposition temperatures and morphology influence grain size and lifetime after CdCl₂ recrystallization. Techniques are developed to estimate grain distribution quickly with low-cost optical microscopy, which compares well with electron backscatter diffraction data providing corroborative assessments of exposed CdTe grain structures. Average grain size increases as a function of CdCl₂ temperature. For lower temperature close-spaced sublimation CdTe depositions, there can be more stress and grain segregation during recrystallization. However, the resulting lifetimes and grain sizes are similar to high-temperature CdTe depositions. The grain structures and lifetimes are largely independent of the presence and/or interdiffusion of Se at the interface, before and after the CdCl₂ treatment.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Renewable Energy. Solar Energy Technologies Office
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1422693
• Report Number(s): NREL/JA-5K00-68664
• Journal Information: IEEE Journal of Photovoltaics, Vol. 8, Issue 2; ISSN 2156-3381
• Publisher: IEEECopyright Statement
• Country of Publication: United States
• Language: English