Synthesis and Modification of Boron Nitride nanotubes using ion implantation

In this work, Chemical Vapour Deposition (CVD) has been used to synthesize boron nitride (BN) nanostructures, particularly nanotubes, and selectively introduce defects into the lattice of the synthesized BN nanostructures through ion implantation. Scanning electron microscopy (SEM) images show clear evidence of BN nanostructures and BN nanotubes (BNNTs), with the latter appearing as long, thin structures with diameters ranging from ⁓30-80 nm. Raman analysis show an E_2g mode of vibration assigned to hexagonal BN (h-BN) at 1366 cm^-1 after ion implantation, with increased intensity. Grazing incidence X-ray diffraction (GIXRD) spectra revealed a prominent peak between 54 and 56°, corresponding to the (004) h-BN reflection, which was used to determine the average lattice parameter c⁓0.662 nm representing the stacking direction of the BN layers. The majority of the samples had broad peaks, indicative of a nanocrystalline material. The only exception was the sample grown at 1200 °C, which was found to have a Scherrer crystallite size >100 nm. In contrast, the rest of the samples had an average size of 3.5 nm. Notable observations in this study include a significant rise in the size of the Raman derived crystallite domains in the nanostructures synthesized at 1100 and 1200 °C after ion implantation with boron ions at fluence 5 × 10¹⁴ ions/cm².