Abstract: In this paper, we report on our efforts intending to understand growth of high quality thin films of organic semiconductor and process of high quality graphene devices via interface engineering with self-assembled monolayers. We first focus on initial growth of metallophthalocyanine and rubrene thin films. Afterwards we extend the interface engineering strategy to graphenen transistors. High performance organic thin film and graphenen transistors are fabricated with record-high carrier mobilities.
The poor crystallinity of organic thin films is an obstacle limiting their practical applications in organic electronics. To solve this problem, we have successfully developed a new strategy of using a few self-assembled monolayers (SAMs), as the template layer to induce the crystallization of metallophthalocyanine or rubrene in vacuum deposition. We have achieved record-high mobility of rubrene and metallophthalocyanine in thin films.
Meanwhile, the SAM strategy is extended to graphene having the two dimensional periodic structure. We investigate the mechanisms of graphene interface coupling to different substrates and interacting with inert adsorbates, both experimentally and theoretically. The charge transfer is unambiguously corroborated by Kelvin probe force microscopy (KPFM) and transport measurement results. The measured temperature dependence of resistivity provides the evident correlation between the transport characteristics and the phonon-electron scattering by the interplay between graphene and the substrate. And a nearly one order of increase in mobility is obtained at room temperature on SiO2/Si substrate.