Formation of single-wall carbon nanotubes catalyzed by Ni separating from Y in laser ablation or in arc discharge using a C target containing a NiY catalyst

Single-wall carbon nanotubes (SWNT) were formed by laser ablation or arc discharge using a C target containing Ni and Y, each with an atomic percentage of 0.3%. The carbonaceous deposit rich in SWNTs contained Ni and a small quantity of Y. The carbonaceous deposit poor in SWNTs contained C, Ni and Y, or C and Y. We concluded that the SWNT formation was catalyzed by Ni, but not by Ni coexisting with Y or by Y itself.