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Title: Visualization of molecular packing and tilting domains and interface effects in tetracene thin films on H/Si(001)

Visualizing molecular crystalline domains and influence of substrate defects are important in understanding the charge transport in organic thin film devices. Vacuum evaporated tetracene films of four monolayers on hydrogen-terminated Si(001)-2x1 substrate, as a prototypical system, have been studied with ex situ atomic force microscopy (AFM), transverse shear microscopy (TSM), friction force microscopy (FFM), and low-energy electron microscopy (LEEM). Two differently oriented in-plane lattice domains are found due to the symmetry of the substrate lattice, with no visible azimuthal twist between adjacent molecular layers in surface islands, indicating significant bulk-like crystallization in the film. Meanwhile, two types of subdomains are observed inside of each in-plane lattice domain. The subdomains are anisotropic in shape, and their sizes and distribution are highly influenced by the substrate atomic steps. TSM and FFM measurements indicate that these subdomains result from molecule-tilt orderings within the bulk-like lattice domains. Lastly, TSM evidently shows a sensitivity to probe vertical molecule-tilt anisotropy for the molecular crystals, in addition to its known ability to map the lateral lattice orientations.
 [1] ;  [2] ;  [1]
  1. Univ. of Guelph, ON (Canada). Guelph-Waterloo Physics Inst., Dept. of Physics
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Publication Date:
Report Number(s):
Journal ID: ISSN 0370-1972; R&D Project: 16083/16083; KC0403020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physica Status Solidi B. Basic Solid State Physics
Additional Journal Information:
Journal Volume: 254; Journal Issue: 7; Journal ID: ISSN 0370-1972
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; boundaries; domains; tetracene; microscopy; microstructures; organic semiconductors; thin films
OSTI Identifier: