Silicon thin film technology has been driven by hydrogenated amorphous and microcrystalline silicon thin films which are routinely produced using silane plasmas. While SiH3 is often considered as the main radical for the obtaining of such films, we have shown that changing the process to conditions where silicon clusters and nanocrystals are produced in the plasma can lead to high deposition rates and improved materials, such as hydrogenated polymorphous silicon and polycrystalline silicon [1]. Moreover, by changing the substrate from glass to crystalline silicon, it is possible to produce epitaxial crystalline silicon films (c-Si:H) which can be transferred to foreign substrates [2,3]. Interestingly enough the structure of c-Si:H films is found to be tetragonal, indicative of their particular growth process [4]. Even more interesting, this low temperature epitaxial process can be extended to doped films as well as to germanium and silicon-germanium alloys and their heteroepitaxial growth on GaAs [5], which opens they way to low cost and high efficiency tandem solar cells. Last but not least, combining PECVD with low melting temperature metal nanoparticles such as indium and tin leads to the growth of nanowires (including Ge, Si and GeSn), which allow to achieve efficient light trapping and carrier collection in radial junction solar cells [6] or even to growth the c-Si nanowires in-plane for stretchable electronics and photonics applications [7].
[1] Ka-Hyun Kim et.al. Sci. Reports 7 (2017) 40553.
[2] R. Cariou et. al. Prog. in Phot.: Research and Applications 24 (2016) pp. 1075-1084
[3] A. Gaucher et. al. NanoLetters 16 (2016) 5358
[4] Wanghua Chen, et.al. Crystal Growth and Design 17 (2017) 4265
[5] Gwenaëlle Hamon, et.al. J. Photon. Energy 7(2), 022504 (2017)
[6] S. Misra et. al. J. Phys. D: Appl. Phys. 47 (2014) 393001.
[7] Zhaoguo Xue et.al. Nature Communications 7 (2016) 12836
