The thermal stress generated by the bimetallic layer of the scroll induces the switching of the growth mode from being in a tightly stacking planar mode to a loosely stacking cage mode. Tightly stacked carbon layers grown at 300 degrees C are consisted of nanoscale graphite, but loosely stacked carbon strips, which are stacks of decoupled graphene layers, are grown at 350 degrees C. However, carbon structures grown on the scrolls at 375 degrees C are nano-onion. (C) 2009 Elsevier B.V. All rights reserved.