Effects of substrate temperature on the growth, structural and optical properties of NiSi/SiC core-shell nanowires

In this paper we attempt to study the growth of NiSi/SiC core-shell nanowires on Ni-coated glass substrates by hot-wire chemical vapor deposition. The samples were prepared at different substrate temperatures of between 350 and 527 °C to investigate the growth of the nanowires. Ni nanoparticles were used as templates for initially inducing the growth of these core-shell nanowires at substrate temperature as low as 350 °C. The high density of the nanowires was clearly demonstrated at higher substrate temperatures of 450 and 527 °C. These core-shell nanowires were structured by single crystalline NiSi and amorphous SiC as the core and shell of the nanowires respectively. The amorphous SiC shell consisted of SiC nanocolumns within an amorphous matrix. The formation of these high density nanowires showed a noticeable suppression in photoluminescence emissions from the oxygen-related defects and superior optical absorption in visible and limited near infrared regions. The effects of substrate temperatures on growth, optical and structural properties of the nanowires are presented and discussed.