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Author Chen, Wanghua ♦ Roca i. Cabarrocas, Pere ♦ Pareige, Philippe
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ DENSITY ♦ DISTRIBUTION ♦ DOPED MATERIALS ♦ ELLIPSOMETRY ♦ HYDROGENATION ♦ IMPURITIES ♦ LASERS ♦ LAYERS ♦ MAPPING ♦ NANOSTRUCTURES ♦ PROBES ♦ RAMAN SPECTROSCOPY ♦ SAMPLE PREPARATION ♦ SILICON SOLAR CELLS ♦ STABILITY ♦ THIN FILMS ♦ X-RAY DIFFRACTION
Abstract Hydrogenated polymorphous silicon (pm-Si:H) is a nanostructured material consisting of silicon nanocrystals embedded in an amorphous silicon matrix. Its use as the intrinsic layer in thin film p-i-n solar cells has led to good cell properties in terms of stability and efficiency. Here, we have been able to assess directly the concentration and distribution of nanocrystals and impurities (dopants) in p-i-n solar cells, by using femtosecond laser-assisted atom probe tomography (APT). An effective sample preparation method for APT characterization is developed. Based on the difference in atomic density between hydrogenated amorphous and crystalline silicon, we are able to distinguish the nanocrystals from the amorphous matrix by using APT. Moreover, thanks to the three-dimensional reconstruction, we demonstrate that Si nanocrystals are homogeneously distributed in the entire intrinsic layer of the solar cell. The influence of the process pressure on the incorporation of nanocrystals and their distribution is also investigated. Thanks to APT we could determine crystalline fractions as low as 4.2% in the pm-Si:H films, which is very difficult to determine by standard techniques, such as X-ray diffraction, Raman spectroscopy, and spectroscopic ellipsometry. Moreover, we also demonstrate a sharp p/i interface in our solar cells.
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-20
Publisher Place United States
Journal Applied Physics Letters
Volume Number 108
Issue Number 25


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