Structure of boron nitride nanotubes
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STRUCTURE OF CRYSTALS
Structure of Boron Nitride Nanotubes Yu. S. Buranova, B. A. Kulnitskiy, I. A. Perezhogin, and V. D. Blank Technological Institute for Superhard and Novel Carbon Materials, Troitsk, Moscow, 142190 Russia email: [email protected] Received September 6, 2013
Abstract—The crystallographic structure of boron nitride nanotubes has been investigated. Various defects that may arise during nanotube synthesis are revealed by electron microscopy. Nanotubes with different num bers of walls and different diameters are modeled by molecular dynamics methods. Structural features of sin glewall nanotubes are demonstrated. The causes of certain defects in multiwall nanotubes are indicated. DOI: 10.1134/S1063774514060054
INTRODUCTION Soon after carbon nanotubes were discovered by Iijima in 1991 [1], researchers started searching for similar tubular structures in other materials. Boron nitride (BN) became the first object of these studies. BN nanotubes were theoretically predicted in 1994 [2] and synthesized for the first time in 1995 [3] (multiwall nanotubes) and in 1996 [4] (singlewall nanotubes). Much attention was paid to these nanotubes in view of their potential applications in nanoelectronics, catal ysis, and the design of new composites. It was estab lished that BN nanotubes have insulating properties [5], are thermally and chemically stable [6], and are characterized by high mechanical parameters [7]. They can be used as cells for storing different materials in gaseous, liquid, or solid states [8]. The first fila ments were made of twisted BN nanotubes in [9]. It is of interest to study the mechanical properties of BN nanotubes, their structure, and the influence of defects on their strength. In this paper we report the results of studying the crystallographic features of BN nanotubes. Different single and multiwall nanotubes were modeled and the structural features of singlewall tubes were consid ered. The structural features of multiwall nanotubes and the peculiar manifestation of defects in them were investigated using electron micrographs and com putersimulation patterns.
consideration of interatomic interactions. The struc tures were described using Tersoff interaction poten tials [10] proposed for BN in [11]. Simulation was per formed using the LAMMPS program [12], and the simulation results were visualized with the aid of Ovito [13] and VMD [14] programs. Micrographs of real nanotubes were obtained with scanning (JSM7600F, secondaryelectron detector, accelerating voltage 0.1–30 3 kV) and transmission (JEM2010 and JEM2100; accelerating voltages 160 and 200 kV, respectively) electron microscopes. An analytical study by scanning electron microscopy (SEM) and TEM was performed using EDS (Inca) and EELS (Gatan) attachments. The thickness of the samples (nanotubes) varied from 20 to 200 nm. Defocusing in electron microscopy analysis was on the order of several tens of nanometers (30–100 nm). The samples of nanotubes for electron microscopy studies were prepared in a high iso
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