Analysis of Defect‐Free Graphene Blocks in Nitrogen‐Doped Bamboo‐Like Carbon Nanotubes

The structure and electronic properties of the N‐doped bamboo‐like carbon nanotubes with different nitrogen content (N‐CNTs) are studied by the use of transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, and X‐ray photoelectron spectroscopy supplemented by measurements of the temperature dependence of conductivity. XPS data are used to estimate the content of nitrogen represented by pyridinic, pyrrolic, graphitic, and oxidized N species and encapsulated molecular nitrogen. The graphene blocks surrounded by borders containing hole defects and N‐species are considered as building blocks of N‐CNT walls. The intensity ratio of D, G, and 2D bands in Raman spectra and XPS data on the concentration of N‐species are used to analyze the size of defect‐free graphene blocks in N‐CNTs. The size of such blocks depends on the N‐defect content and is estimated to be 1–2 nm. The increase of N‐species content resulting in a decrease of graphene block size correlates with the decrease of current carrier concentration (nES) estimated within the Efros–Shklovskii model. The size of defect‐free graphene blocks in nitrogen‐doped carbon nanotubes was estimated to be 1–2 nm and correlated with nitrogen content in the tubes.