The influence of γ-irradiation on nitrogen configuration in nitrogen-doped single-walled carbon nanotubes

Electronic properties of nitrogen-doped single-walled carbon nanotubes (N-doped SWCNTs) depend on carbon and nitrogen configuration. Depending on the intrinsic nitrogen structure, it can be either intrinsic p- or n- doping. Here, we have investigated the influence of soft gamma (γ)-irradiation on the nitrogen configuration in vertically aligned N-doped SWCNT arrays. As the irradiation dose increased, pyridinic and graphitic nitrogens become more predominant. In general, the presence of holes refer to p-doping. However, XPS spectra show n-doping features, whereas the slight downshift in the G line position in Raman spectra is from compensating the ambient p-doping. The local transition of π* nitrogen was also revealed by X-ray absorption spectroscopy.