Fig. 4.

Hydrogen attacking of SWNTs. AFM images of nanotubes on a substrate recorded before (A) and after (B) H₂ plasma treatment (5% in argon, total pressure = 0.5 torr, radio-frequency power = 20 W) at 500°C for 10 min. The treatment was carried out in the same chamber used for growth of the V-SWNTs with only the H₂/Ar gas flow. The after-etching image in B clearly shows that some of the nanotubes in A were etched by H plasma. SWNTs are also found to be etched by H plasma at room temperature (not shown).