Ultra-thin and high-aspect-ratio TiN nanosheets

Ultra-thin and high-aspect-ratio titanium nitride (TiN) nanosheets were successfully synthesized by a chemical vapor deposition method using TiCl4 and N-2 as source materials without catalyst assistance. Nanosheet thickness was around 3.2 nm determined from atomic force microscopy (AFM) and electron energy-loss spectrometer (EELS) measurements. According to FESEM images, length of nanosheet ranged from 5 to 20 mu m, indicating that the nanosheets had the high aspect ratio in the range between 1500 and 5500. Because of the extremely thin thickness, translucent TiN nanosheets were capable of exhibiting bending, folding, as well as rolling. The 1/3{2 2 0} and 1/3{4 2 2} forbidden reflections were observed in SAED patterns, confirmed by the observation of the threefold {4 2 2} lattice fringes in high-resolution transmission electron microscopy (HRTEM) image. The observed and possible minor phases such as TiSi2, Si3N4 and titanium oxynitride probably resulted from the complex reactions involving TiCl4, TiN and Si substrates. (C) 2007 Elsevier B.V. All rights reserved.