Aligned Si_3N_4@SiO_2 coaxial nanocables derived from a polymeric precursor

摘要

Well-aligned coaxial nanocables, composed of a crystalline α-Si _3N_4 inner core and amorphous SiO_2 outer shell, were prepared on silicon substrates by pyrolysis of a preceramic polymer (perhydropolysilazane) with iron as catalyst. The nanocables have high density, and the longest nanocable can be up to millimeters. Photoluminescence measurement reveals a strong ultraviolet emission band centered at 360nm and a weaker visible-light emission at 625nm. The growth mechanism of the nanocables is discussed in detail.