Coexistence of Closely Packed c(4 x 2) and Striped Phases in Self-Assembled Monolayers of Decylthiocyanates on Au(111)

Decylthiocyanate (DTC) self-assembled monolayers (SAMs) on Au(111) were prepared by solution and vapor phase deposition methods at 50 degrees C for 24 h The formation and surface structure of DTC SAMs were examined using scanning tunneling microscopy (STM) STM imaging revealed that DTC SAMs formed in 1 mM ethanol solution at 50 degrees C were composed of small ordered domains with lateral dimensions of a few nanometers and disordered phases, whereas DTC SAMs formed in the vapor phase at 50 degrees C contained two ordered phases a closely packed c(4 x 2) superlattice and a striped phase with an mterstripe spacing of 26 - 2 8 nm It was also found that the ordered domain and vacancy island formation for DTC SAMs on Au(111) differs significantly from that of decanethiol SAMs, suggesting that adsorption mechanism is different from each other From this study, it was confirmed that DTC SAMs with a high degree of structural order can be obtained by vapor phase deposition.This work was supported by National Research Foundation of Korea Grant funded by the Korean Government (KRF-2008-314-C00095) This work was also supported by the research fund of Hanyang University (IIYU-2009-T). the Seoul R&BD Program (10919) and the Korea Foundation for International Cooperation of Science and Technology through a grant provided by the Korean Ministry of Science and Technology (No K20501000002-07-E0100-00210