High performance and high stability mechanisms of microcrystalline silicon-based thin-film solar cells deposited by laser-assisted plasma-enhancement chemical vapor deposition system

Abstract

The laser-assisted plasma-enhanced chemical vapor deposition (LAPECVD) system was proposed to deposit high performance and high stability Si-based thin-film solar cells. In the LAPECVD system, the CO2 laser and plasma were simultaneously utilized to effectively decompose the SiH4 reaction gas. Consequently, the hydrogen concentration in the i-Si absorption film was reduced with an increase of CO2 laser power. Furthermore, the microcrystalline i-Si film could be formed due to the formation of more Si nucleation seeds. Si-nanoclusters were formed on the microcrystalline i-Si films deposited in the LAPECVD system. The associated carrier mobility was increased with increasing the CO2 laser power. The XRD measurements demonstrated that a gradual transformation from amorphous to crystalline as guiding the assisting laser. According to the FTIR measurement, the estimated hydrogen content reduction ratio of the light-soaked i-Si films decreased from 16.5% to 5% as the assisting laser power increased from 0W to 80W. The corresponding conversion efficiency degradation ratio of 20.20% and 5.74% was obtained, the high performance and high stability of the resulting Si-based p–i–n thin film solar cells were obtained.