Copper phthalocyanine thin films on Cu(111): Sub-monolayer to multi-layer

摘要

Scanning tunneling microscopy (STM) has been used to observe the growth mode and crystal structure of submonolayer (ML) to multilayer thin films of copper phthalocyanine (CuPc) molecules on the Cu(111) surface as room temperature (RT). At sub-ML coverage the molecules are mobile on the surface. At approximately one ML coverage the molecules become sterically confined and lying flat on the Cu substrate form an ordered, multi-domained, 2D oblique lattice. As coverage is increased beyond 1 ML the molecule-substrate interaction diminishes in strength while the intermolecular interaction begins to dominate, causing the layer separation to increase, and the crystal domain size and lattice constants to shrink as the crystal structure begins to more closely resemble the bulk alpha-phase CuPc molecular solid. This trend continues for the layer-by-layer growth of 3 complete ML, eventually giving way to the emergence of large 3D islands at a coverage equivalent to 4 ML (C) 2015 Elsevier B.V. All rights reserved.