Applied Surface Science, Vol.493, 497-505, 2019
Effect of stacking fault nanolayers on the photoluminescence properties of SiC nanowires
Two types of SiC nanowires were synthesized via carbothermal reduction and subsequent wet chemical etching. Both SiC nanowires consisted of cubic beta-SiC and exhibited numerous stacking fault nanolayers. The etching process was very selective to the stacking fault nanolayers and beta-SiC; beta-SiC was gradually corroded; however, the stacking faults were retained. Three strong and distinct photoluminescence (PL) emission peaks emerged in the PL spectra of both types of SiC nanowires as the excitation wavelength was increased from 290 to 490 nm. The strong ultraviolet emission and the blueshift of the PL peak were related to the quantum confinement effects of the stacking fault nanolayers having a thickness of < 3 nm. This quantum confinement effect was responsible for the blue emission observed from the SiC nanowires. The thickness of the nanolayers was in good agreement with the theoretically predicted value (3-5.4 nm). The additional green emission and blueshift of the peak arose from surface structures induced by Si-O and Si-OH. The green emission required a sufficiently large surface area and was only observed using longer-wavelength excitation to excite more SiC nanowires with larger sizes.