One Dimensional Van Der Waals Heterostructures Wrapped Around Single-Walled Carbon Nanotubes

Abstract

We have synthesized a new coaxial nanotube structure, in which mono- or few-layer hexagonal boron nitride nanotube (BNNT) seamlessly wrap around a single-walled carbon nanotube (SWCNT), and result in an atomically smooth coaxial tube consisting two different materials, as shown in Fig. 1(a). TEM-EELS clearly demonstrated the BNNT-SWCNT coaxial structure. We have tried various morphologies of SWCNTs as starting material, e.g. vertically aligned array, horizontally aligned array, suspended SWCNTs, and dry-deposited random network films. We can clearly observe the coaxial structure from originally isolated SWCNTs. We found no correlation between chiral angle of inner SWCNT and outer BNNT for ‘double-walled’ SWCNT-BNNT shown in Fig. 1(b). We concluded that these are one-dimensional van der Waals heterostructure. We have further developed the 1D coating CVD for transition metal dichalcogenide nanotubes, such as MoS2 nanotube as shown in Fig. 1 (c). We can grow MoS2 nanotubes around relatively large diameter SWCNT or SWCNT@BNNT [1]. We will discuss properties of the 1D heterostructures though optical absorption, Raman scattering, photoluminescence, FT-IR, and cathode luminance. Reference: [1] Rong Xiang et al., arXiv:1807.06154 (2018). Figure 1