Comprehension of the S(V)LS mechanism growth of silicon-based nanowires

摘要

A comprehensive thermodynamic assessment has been carried out on the Au-Si-O system involved in the growth mechanism of Silicon NanoWires (SiNW) via the solid-liquid-solid process.The driving force needed to trigger the SiNW precipitation is supersaturation of liquid alloy Au-Si.Our model demonstrates,for the first time,how and from where supersaturation is reached.Supersaturation is not due to the migration of silicon from the wafer as claimed by many researchers,but to the existence of SiO volatile species resulting from the metastable equilibrium SiO_(2,amorphous)/Si_(wafer).More interesting is that the partial pressure P_(sio) does impose an initial minimum radius of the first generation of nanowires in the range of 10 nm.After that,other generations of nanowires will grow due to the new metastable equilibrium SiO_(2,amorphous)/Si_(nanowire).