Ordered copper phthalocyanine overlayers on InAs and InSb (100) surfaces

Low-energy electron diffraction (LEED) has been used to investigate the ordered structures formed when copper phthalocyanine (CuPc) is vapour-deposited at room temperature on to the indium-terminated InSb(100) and InAs(100) (4 x 2)/c(8 x 2) reconstructed surfaces. After deposition of up to two monolayers (ML) of CuPc, a (3 x 3) structure is formed on InSb(100) and a (root 10 x root 10)R +/- 18.4 degrees structure is observed on InAs(100). The formation of ordered CuPc overlayers on these surfaces suggests that the molecule-surface interaction is surprisingly weak, despite the presence of dangling bonds, and there is sufficient lateral diffusion of the molecules to allow ordered crystalline domains to be formed. By contrast, no ordered structures are observed for CuPc deposition On related III-V semiconductor surfaces that are terminated with gallium or antimony; e.g., GaAs(100)-(4 x 2)/c(8 x 2), GaSb(100)-(1 x 3) GaSb(100)-c(2 x 6) and InSb(100)-c(4 x 4). The results are discussed in terms of the lattice size and the chemical composition of the substrate surface. (C) 1999 Elsevier Science B.V. All rights reserved.