Coverage-dependent adsorption superstructure transition ofC60/Cu(001)

Abstract

We have investigated the growth and structure of a C 60 monolayer film on Cu͑001͒ with scanning tunneling microscopy at room temperature and 100 K. We discovered that the equilibrium adsorption structure of annealed C 60 films depends sensitively on the initial deposition coverage; for a coverage of 0.5 monolayer C 60 orders in an one-bright-and-one-dim ͑1B1D͒ row sequence along the ͓110͔ direction whereas for a coverage close to one monolayer C 60 orders in a two-bright-and-one-dim ͑2B1D͒ sequence. At the transition region of the bright and dim row segments, C 60 often appears "frizzy" at room temperature. This indicates that a C 60 rotates and adopts molecular orientations with inequivalent symmetry. Upon annealing, the C 60 film exhibits a high thermal stability before C 60 fragmentation and desorption occur at ϳ880-960 K, depending on its adsorption superstructure. The duality of equilibrium superstructure in C 60 / Cu͑001͒ is unique among studied C 60 monolayers on metals. We argue that different boundary energy of the 1B1D and 2B1D phases offers a plausible explanation on the observed tunability of superstructure versus coverage.

Survey of structural and electronic properties of C60 on close-packed metal surfaces

“…The adsorption structures depend not only on the thermal history of the sample but they are also sensitive to the initial deposition coverage [33,[70][71][72]. For example, on Cu(100), STM reveals that for an initial coverage of 0.5 monolayer, C 60 orders in a one-bright-andone-dim row sequence along the [110] direction, whereas for a coverage close to one monolayer, C 60 orders in a twobright-and-one-dim sequence [71].…”

“…The adsorption structures depend not only on the thermal history of the sample but they are also sensitive to the initial deposition coverage [33,[70][71][72]. For example, on Cu(100), STM reveals that for an initial coverage of 0.5 monolayer, C 60 orders in a one-bright-andone-dim row sequence along the [110] direction, whereas for a coverage close to one monolayer, C 60 orders in a twobright-and-one-dim sequence [71]. For C 60 on Al(111), STM studies have shown that one molecule out of three protrudes from the surface upon reconstruction, and DFT calculations suggested an irreversible (6 9 6) reconstruction of the system from the (2H3 9 2H3)R30°phase [19,20].…”

Orientation Ordering and Chiral Superstructures in Fullerene Monolayer on Cd (0001)

“…A variety of C 60 monolayers grown on solid surfaces is critical for understanding and controlling the interface properties of fullerene-derived electronic and photovoltaic devices [ 1 , 2 , 3 ]. In the past decades, there have been a large number of investigations of C 60 monolayer structures grown on a wide range of metallic or semiconducting substrates such as Ag [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ], Au [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], Cu [ 24 , 25 , 26 , 27 , 28 ], graphene [ 29 , 30 , 31 , 32 , 33 ], Si [ 34 , 35 , 36 ], Ge [ 37 , 38 , 39 ], or NaCl [ 40 ]. It was found that almost all monolayers of C 60 adopt a close-packed structure regardless whether the substrate is isotropic or anisotropic, metallic or nonmetallic.…”

Self-assembled C60 layers on incommensurate Cu/Si(111)‘pseudo-5 × 5’ surface

“…At the stage of island growth, difference in C 60 adsorption energy 44 for different sites can be utilized to improve spatial ordering of the mo-45 lecular islands [1][2][3][4] and to sharpen their size distribution [1,5]. When 46 extended C 60 arrays are formed, difference in C 60 adsorption geometries leads to developing modulations in the molecular layers which typically 48 appear as regular occurrence of fullerenes displaying different contrast, 49 bright and dim, in scanning tunneling microscopy (STM) images [6][7][8][9][10][11][12][13][14]. 50 Incommensurate surfaces constitute an interesting class of reconstruct-51 ed surfaces [15].…”