The structural changes in C-60/C-70:Ni layers annealed at a temperatur
e of 620 K were observed by Raman spectroscopy, electron diffraction,
AFM and HRTEM methods. The 'as grown' C60C/(70):Ni layers exhibit the
features of the amorphous structure, which is confirmed by broadened R
aman bands of H-g(1) fullerene mode, diffused rings in the electron di
ffraction pattern (with 4.8 and 8.7 nm(-1) radius) and HRTEM pictures.
The AFM topographies depict grains of 100-200 nm in size, rounded hil
locks agglomerated in bigger 'zigzag' objects. The annealed layer cont
ains two phases: amorphous and crystalline fcc C-60 with enlarged latt
ice parameter (a = 1.44 nm). The changes toward crystalline structure
are observed in Raman spectra (sharp H-g(1)mode) and in the electron d
iffraction pattern (reflexes (111), (220), (311), (420) and (422) of p
ure C-60 fee structure). The AFM topographies show two kinds of object
s with different lateral sizes 300 and 100-200 nm and different base t
o top height 100-150 and 35 nm, respectively. (C) 1997 Published by El
sevier Science Ltd.