熔盐电解法制备硅纳米线及其生长过程研究

Study on Micro-structural Growth of Silicon Nanowire Prepared by Molten Salt Electrolysis

结合熔盐电解法制备了数微米长、200nm左右宽的纳米级硅线。采用预烧结的多孔SiO2粉末为阴极、等摩尔比的CaCl2-NaCl混合熔盐为电解质、石墨棒为阳极,在700℃、1.8V槽电压下通电5h后获得产物单质Si。研究了单质Si在电化学形核及后续生长过程中的微观结构及形貌演变规律,发现在晶体Si电化学形核后逐渐堆积形成"珠串"状结构,构成了硅线的雏形,在高温作用下,该结构继续生长最终形成纳米级硅线结构。

Nano-sized silicon wire with several micrometers in length and about 200 nm in width was prepared by molten salt electrolysis process.Metallic silicon was produced by electrolysis at 700℃ for 5 h under 1.8 Vcell voltage applying pre-sintered porous SiO2 powder as cathode,equimolar CaCl2-NaCl mixed molten salt as electrolyte,and graphite rod as anode.The micro-structure and morphology evolution of metallic silicon were studied just after silicon is electrochemical nucleated and further grew.The results suggest that after silicon is electrochemical nucleated,the crystalline is accumulated together to form ‘bead string’structure,which constitutes rudiment of silicon nanowire.The‘bead string’structure constantly grows to form final nanoscale silicon wire under high operation temperature.