resumo
Self-assembly of ferroelectric materials attracts significant interest because it offers a promising fabrication route to novel structures useful for microelectronic devices such as nonvolatile memories, integrated sensors/actuators, or energy harvesters. In this work, we demonstrate a novel approach for self-assembly of organic ferroelectrics (as exemplified by ferroelectric beta-glycine) using evaporative dewetting, which allows forming quasi-regular arrays of nano- and microislands with preferred orientation of polarization axes. Surprisingly, self-assembled islands are crystallographically oriented in a radial direction from the center of organic grains formed during dewetting process. The kinetics of dewetting process follows the t(-1/2) law, which is responsible for the observed polygon shape of the grain boundaries and island coverage as a function of radial position. The polarization in ferroelectric islands of beta-glycine is parallel to the substrate and switchable under a relatively small dc voltage applied by the conducting tip of piezoresponse force microscope. Significant size effect on polarization is observed and explained within the Landau-Ginzburg-Devonshire phenomenological formalism.
palavras-chave
THIN POLYMER-FILMS; CRYSTALS; GROWTH; MEMORY; CRYSTALLIZATION; LITHOGRAPHY; ARRAYS
categoria
Science & Technology - Other Topics; Materials Science
autores
Seyedhosseini, E; Romanyuk, K; Vasileva, D; Vasilev, S; Nuraeva, A; Zelenovskiy, P; Ivanov, M; Morozovska, AN; Shur, VY; Lu, HD; Gruverman, A; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Principal
Ensieh Seyedhosseini
Estudante de doutoramento
Konstantin Nikolaevich Romanyuk
Investigador Júnior
Maxim Ivanov
Investigador Júnior
Pavel Zelenovskii
InvestigadorGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
agradecimentos
The equipment of the Ural Center for Shared Use "Modern nanotechnology" UrFU was used. This work was funded by the Luso-American Foundation (FLAD) (grant no. 299/2015). K.R. is grateful to the financial support of FCT via his postdoctoral grant SFRH/BPD/88362/2012. Part of this work was developed in the scope of project CICECO-Aveiro Institute of Materials (ref FCT UID/CTM/50011/2013), financed by national funds through the- FCT/MEC and, when applicable, cofinanced by FEDER under the PT2020 Partnership. P.Z. is grateful for support from the Ministry of Education and Science of the Russian Federation through the RF President grant for young scientists MK-6554.2015.2. M.I. is grateful to the RFBR through research project no. 16-32-60188 mol_a_dk. The authors are grateful to Ohheum Bak for the help with experimental work.