Order and disorder in C60 and K(x)C60 multilayers - Direct imaging with scanning tunneling microscopy

Monolayer and multilayer structures of C60, a high temperature van der Waals solid, have been studied with scanning tunneling microscopy. Structures grown on GaAs(110) at 300 K and at elevated temperatures show significantly different morphologies because of balances between thermodynamics and kinetics. Condensation onto stepped surfaces demonstrates preferred bonding and nucleation at step edges. Detailed studies of potassium incorporation in crystalline C60 show highly ordered structures in the K3C60 metallic state but disordered nonmetallic structures for high potassium concentrations.