Preparation of 2H/3C–SiC heterojunction nanowires from molten salt method with blue shift photoluminescence property

Silicon carbide nanowires (SiC NWs) were successfully synthesized using graphene and Si powder as raw materials in NaCl–NaF at 1300–1400 °C for 6 h. The synthesized SiC NWs have two crystal phases due to the presence of molten salt, which formed the 2H/3C–SiC heterojunction structure. The possible synthesis mechanism of SiC NWs is “dissolution-diffusion-reaction”. Besides, photoluminescence (PL) spectra of 2H/3C–SiC heterojunction NWs show that the main emission peak has a significant blue shift, locating in 350–600 nm. The main reason is caused by the defects of 2H/3C–SiC heterojunction structure and the spontaneous polarization of 2H–SiC nano segments.