Conversion of vertically-aligned boron nitride nanowalls to photoluminescent CN compound nanorods: Efficient composition and morphology control via plasma technique

Two-dimensional BN/CN nanomaterials of various composition and morphology were synthesized in N₂[sbnd]H₂ plasma by plasma-enhanced hot filament chemical vapor deposition, with B₄C used as precursor. The results of field emission scanning electron microscopy, X-ray diffractometer, transmission electron microscopy, micro-Raman and X-ray photoelectron spectroscopy evidence that the hexagonal boron nitride nanowalls with carbon and oxide phases were synthesized under about 1:1 ratio of H₂ to N₂, while the CN nanorods with boron and oxide phases are formed under other ratios of H₂ to N₂, and the nanowires made of oxide phases are grown without the plasma. Efficient control over the nanostructure composition and morphology was demonstrated, thus proposing a cheap and convenient fabrication technique for the advanced composite boron nitride/graphene materials. The photoluminescence properties of the synthesized BN and CN nanomaterials were also studied using the 325 nm line of He[sbnd]Cd laser as the excitation source. The fabricated nanomaterials can generate the ultraviolet, blue and green multi-PL bands, which are associated to the defects formed in these nanomaterials and the carbon clusters, respectively. These outcomes can make a great contribution to the design of functional BN- and CN-nanomaterials of various morphologies and compositions for the applications in various electronic and carbon-based optoelectronic nanodevices.