C60 films on surface-treated silicon: recipes for amorphous and crystalline growth

C 60 films up to 1000 A in thickness have been grown by room-temperature sublimation onto Si(100) and Si(111) substrates that have been prepared with surfaces passivated against dangling bonds. X-ray diffraction measurements reveal that films deposited on such substrates have a high degree of (111)-textured crystallinity which is absent in films deposited on untreated Si. Examination of surface topographies with tapping mode atomic force microscopy shows a thickness-dependent increase in roughness which is greater for the treated samples. Our results are placed in context with respect to what is presently known about the growth of C 60 films on a variety of substrates. Implications for possible device applications will also be discussed.