Effect of substrate nanopatterning on the growth and structure of pentacene films

摘要: The effect of modulating the structure thin pentacene (C22H14) films by a nanopatterned inert substrate, known as hexagonal boron nitride nanomesh, is reported. Films different thickness are grown and characterized x-ray absorption, core-level photoemission, low-energy electron microscopy, microbeam diffraction, scanning tunneling microscopy. Initially molecules adsorb with molecular plane lying flat on substrate but they tend to flip up increasing coverage, forming well-ordered monolayer-thick islands upright low nucleation density. herringbone packing observed electronic adsorbed very similar that gas-phase pentacene, implying weak interaction between molecules. periodic corrugation surface causes monolayer form two coincidence superstructures. lattice parameters unit cell for each these substrate-induced domains determined from microdiffraction patterns. Both can occur in several equivalent configurations, thus resulting number twins typical size few micrometers. first grows layer-by-layer mode until it completed while second forms diffusion-limited fractal islands. Upon annealing, thermally stable approximately 80 degrees C thereafter onset desorption observed.