Fig. 4.

a Schematic of the catalytic chemical vapor deposition (CCVD) and b TEM image of the double-walled BNNT produced by CCVD method. c 200 mg of BNNTs synthesized by boron oxide chemical vapor deposition (BOCVD) at 1500 °C over 1 h. Images of d SEM and e TEM of as-grown BNNTs by BOCVD, inset A and B in e are corresponding SAED and FFT patterns.

(a, b Reprinted with permission from [40], copyright 2008 American Chemical Society. c–e Reproduced with permission from [44], copyright 2005 Elsevier B.V. All rights reserved)