This study deals with the growth mode of N,N′-dipenthyl-3,4,9,10- perylenetetracarboxylic diimide (PTCDI-5C) thin films from less than 1 monolayer to 23 monolayers thick. The effects of growth temperature and the thickness and nature of the substrates-SiO2 on Si(001) or octadecyltrichlorosilane (OTS) self-assembled monolayer terminated Si(001) surfaces-are discussed. Thin films were deposited from a homemade Knudsen cell by using a hot-wall deposition technique. Films were analyzed by atomic force microscopy, X-ray diffraction, and X-ray reflectivity. Films exhibited a (001) orientation with a 1.63 nm d spacing, and a metastable thin film phase was observed without any distinction of the nature of the substrate. However, differences were noticed in the early stages of growth: PTCDI-5C/SiO2 first monolayers presented a Stransky-Krastanov growth mode, whereas PTCDI-5C/OTS first monolayers showed a more complex mode with incomplete wetting of the substrate surface. Differences between the two morphologies softened as the film thickness increased.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films