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High-performance a-SiGe:H thin film prepared by plasma-enhanced chemical vapor deposition with high plasma power for solar-cell application

Authors

  • Baojun Yan,

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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  • Lei Zhao,

    Corresponding author
    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
    • Phone: +86 10 82547042, Fax: +86 10 82547041
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  • Bending Zhao,

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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  • Jingwei Chen,

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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  • Guanghong Wang,

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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  • Hongwei Diao,

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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  • Wenjing Wang

    1. Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing 100190, P.R. China
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Abstract

Hydrogenated amorphous silicon germanium (a-SiGe:H) thin films were prepared by a 13.56-MHz plasma-enhanced chemical vapor deposition (PECVD) method. The optical, optoelectronic, and microstructure properties of the a-SiGe:H thin films prepared with different plasma powers were investigated systematically by transmission, photo/dark conductivity, Raman, and Fourier transform infrared (FTIR) spectroscopy measurements. It was found that when the deposition pressure was high and the hydrogen (H2) dilution ratio ([H2]/([SiH4] + [GeH4])) was low, an appropriate high plasma power could enlarge the optical bandgap (Eg) by reducing the Ge content in the thin film, enhance the film photosensitivity by improving the film microstructure, and increase the film growth rate. As a demonstration, excellent a-SiGe:H thin film with Eg of 1.5 eV, the photosensitivity of above 104 and a growth rate of 6.6 Å s−1 was successfully fabricated for the solar-cell application with a plasma power density of 400 mW cm−2, a deposition pressure of 3 Torr, and a H2 dilution ratio equal to 3 at 220 °C. The underlying mechanism was further analyzed.

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