Low-temperature synthesis of Si and Si-based compounds using Na

Low-temperature solution growth of Si crystals using Na was demonstrated based on the Na-Si binary phase diagram. Single crystals, films, porous bulk samples, and helical microtubes of Si crystals were prepared from a Na-Si solution by Na evaporation. Dissolution and crystallization of Si in a Na melt reduced the impurity content in the Si crystals. Low-temperature synthesis and morphology control of porous SiC ceramics using Na were also performed and a new ternary compound, Na₈B_74.5Si_17.5, was synthesized.