Fig. 2: Characterization of the ion-implanted catalysts. | Nature Communications

Fig. 2: Characterization of the ion-implanted catalysts.

From: Nano-seeding catalysts for high-density arrays of horizontally aligned carbon nanotubes with wafer-scale uniformity

Fig. 2

a TOF-SIMS depth profile curves of iron-implanted sapphire before and after annealing and b 2D-mapping images of Fe ion intensity extracted at increasing depths, showing the variation trend of Fe ions over depth of sapphire substrate. Color scale represents the secondary ion intensity. c–e Cross-sectional STEM image c of an ion-implanted sapphire substrate and the corresponding EDS mappings of Fe (yellow) (d) and Al (purple) (e) elements. Inset in (c) is the FFT pattern of sapphire cross section (scale bar 2 nm−1). f High magnification STEM-HAADF image demonstrated the substitution of Fe atoms for Al atoms in the surface of sapphire after annealing. g–i TOF-SIMS 3D structural reconstruction of Fe ions (red) and Al ions (blue). Fe ions concentrated in specific depth of sapphire after implantation g and distributed uniformly throughout the sapphire matrix after annealing (h). The distribution of Al ions remained after annealing (i). j–k Regulation of growing process of HACNT arrays by the ion energy (j) and the ion fluence (k) of ion implantation. The pink columns in j displayed the influence of ion energy on optimal growing time (\(T\)). The blue columns in (k) displayed the influence of ion fluence on optimal hydrogen to carbon (\(H/C\)) ratio. Source data are provided as a Source Data file.

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