Synthesis of crystalline Si-based nanosheets by extraction of Ca from CaSi2 in inositol hexakisphosphate solution

Crystalline Si-based nanosheets were successfully synthesized from CaSi2 by a simple soft chemical synthetic method in solution. By immersing CaSi2 powder or CaSi2/Si substrates in an inositol hexakisphosphate (IP6) solution, Ca atoms were extracted from the CaSi2 particles, then Si-based nanosheets were formed. The morphological, structural and optical properties of the Si-based nanosheets were investigated. It is noted that the thin Si-based nanosheets stacked with a void space formed bundle structures, and the nanosheets were easily exfoliated from the bundles to expose the surfaces corresponding to the Si{111} planes. Meanwhile, the surface of the Si nanosheets might be terminated by O, H, or OH bonds. The Si-based nanosheet bundles were then formed and directly rooted to the Si(111) substrates, and had a remarkably highly symmetrical morphology. This study demonstrated a simple method for preparing Si-based nanosheets, and electro- and photo-chemical applications would possibly be expected, such as in lithium ion batteries. (C) 2017 The Japan Society of Applied Physics