Abstract SiC nanowires including ultra-thin, hierarchical, bamboo-like, beaded-like and core-shell nanowires were successfully synthesized via carbothermal reduction method without using catalyst. The microstructures and diameter were controlled by reaction temperature… Click to show full abstract
Abstract SiC nanowires including ultra-thin, hierarchical, bamboo-like, beaded-like and core-shell nanowires were successfully synthesized via carbothermal reduction method without using catalyst. The microstructures and diameter were controlled by reaction temperature ranging from 1500 to 1600 °C, holding time from 2 to 4 h and different raw materials. Notably, the diameter of ultra-thin SiC nanowires was ranging from 8 to 20 nm. Photoluminescence properties of obtained nanowires with unique microstructures were investigated at room temperature. It indicates that the primary emission peaks locate in the blue/violet band range of 350∼500 nm with obvious blue shifts. Meanwhile, the luminescence mechanism of SiC nanowires is discussed in detail. The ultra-thin SiC nanowires exhibit the highest intensity because of the strong quantum confinement effect and the quasi-direct band gap. Due to the strong defects effect of twin segments, hierarchical and bamboo-like nanowires with high stacking faults and rough surface show higher intensity under 263 nm excitation. While beaded-like and core-shell nanowires with SiO2 shell and smooth surface exhibit a noticeable increase in the intensity under 318 nm excitation. This might be ascribed to the neutral oxygen vacancies and oxygen atoms.
               
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