Condition of Si crystal formation by vaporizing Na from NaSi

NaSi was heated at various Na vapor pressures (pNa 0.1–1.2 atm) and temperatures (973–1173 K) to investigate the condition of Si crystal formation from NaSi by Na evaporation. Silicon single crystals 1–3 mm in diameter were grown by evaporation of Na from Na–Si melt at 1173 K and pNa=0.74 atm.

► We investigated the formation of Si and NaSi at various temperatures and Na vapor pressures.
► We revealed the condition of Si crystallization from Na–Si melt.
► Si single crystals of about 1–3 mm were obtained by evaporation of Na from Na–Si melt.