Surface chemical composition of SiC-cored nanowires investigated at room and elevated temperatures in ultra-high vacuum

Nanowires with SiC core were produced via Si/PTFE combustion synthesis in air and deposited from 1,2-dichloroethane suspension on an Au (111) surface. The dependence of the chemical bonding states on temperature (300–673 K) between different elements being a building material of nanowires' sidewalls was investigated by X-ray photoelectron spectroscopy (XPS) in ultra-high vacuum (UHV) conditions. Apart from silicon and carbon, the presence of oxygen and nitrogen was observed. Moreover, Si3N4 seems to be the second most important compound (after SiC) forming the amorphous outer shell of SiC nanowires. It is shown that carbon-containing compounds (oxides, nitrides, hydrocarbons) are substantially removed under annealing. It is also reported that a noticeable part of subsurface oxygen in the outer shell reacts with nitrogen at 473–573 K forming stable N–O bonds on nanowires' surface. ▸ We produce SiC-cored nanowires via combustion synthesis in air. ▸ We investigate SiC-cored nanowires at 300–673 K in ultra-high vacuum. ▸ The nanowires’ surface is composed of SiC and compounds containing N and O. ▸ The surface reaction occurs at 473–573 K leading to the formation of N–O bonds.