[18a-G205-1~8] 12.1 Fabrications and Structure Controls

[18a-G205-7] Molecular Dynamics Simulations of Organic Graphoepitaxy 5 (final)
– Summary of the groove wall effect and prospect of application to film growth theory –

〇Susumu Ikeda¹ (1.WPI-AIMR, Tohoku Univ.)

Keywords:graphoepitaxy, molecular dynamics simulations, organic semiconductor

In the previous JSAP meetings, I have reported some results of molecular dynamics (MD) simulations reproducing the graphoepitaxial growth of organic semiconductors, sexithiophene (6T) and pentacene. It can be said that MD simulations are among the most useful tools to investigate the mechanism of organic graphoepitaxy at the molecular level according to my results. In particular, I performed MD simulations of the dynamic deposition process of pentacene molecules and could reproduce the appearance of clusters (nuclei) comprising standing molecules on the substrate. Organic semiconductor molecules tend to lie on the substrate because of the interaction between the molecules and the substrate surface, and it has been difficult by MD simulations to reproduce the nucleation and growth of organic thin films (crystals) consisting of standing molecules. However, in the MD simulations of graphoepitaxy, by the effect of the groove wall, standing molecules formed clusters (nuclei) spontaneously. This fact brings us a new idea that some kind of defects or surface roughness can assist the formation of organic thin films comprising standing molecules. I am planning to further investigate this issue and reconsider the general theory of nucleation and thin film growth of organic semiconductors.