title: Self-assembled diacetylene molecular wire polymerization on an insulating hexagonal boron nitride (0001) surface.
abstract: The electrical characterization of single-polymer chains on a surface is an important step towards novel molecular device development. The main challenge is the lack of appropriate atomically flat insulating substrates for fabricating single-polymer chains. Here, using atomic force microscopy, we demonstrate that the (0001) surface of an insulating hexagonal boron nitride (h-BN) substrate leads to a flat-lying self-assembled monolayer of diacetylene compounds. The subsequent heating or ultraviolet irradiation can initiate an on-surface polymerization process leading to the formation of long polydiacetylene chains. The frequency of photo-polymerization occurrence on h-BN(0001) is two orders of magnitude higher than that on graphite(0001). This is explained by the enhanced lifetime of the molecular excited state, because relaxation via the h-BN is suppressed due to a large band gap. We also demonstrate that on-surface polymerization on h-BN(0001) is possible even after the lithography process, which opens up the possibility of further electrical investigations.
authors: International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. Institute of Physics, Czech Academy of Sciences, Na Slovance, 2, Prague 8, 18221, Czech Republic.
authors: Marina V
authors: MV
authors: Makarova
authors: Yuji
authors: Y
authors: Okawa
authors: Elisseos
authors: E
authors: Verveniotis
authors: Kenji
authors: K
authors: Watanabe
authors: Takashi
authors: T
authors: Taniguchi
authors: Christian
authors: C
authors: Joachim
authors: Masakazu
authors: M
authors: Aono