A Study on the Growth Behavior and Stability of Molecular Layer Deposited Alucone Films Using Diethylene Glycol and Trimethyl Aluminum Precursors, and the Enhancement of Diffusion Barrier Properties by Atomic Layer Deposited Al2O3 Capping.
As a route to the production of organic-inorganic hybrid multilayers, the growth behavior of molecular layer deposited (MLD) alucone and atomic layer deposited (ALD) Al2O3 films on top of each other was examined. MLD alucone films were prepared using trimethyl aluminum and diethylene glycol precursors, the latter resulting in faster growth rates than ethylene glycol precursors. The sensitivity of individual alucone films with respect to ambient exposure was found to be related to moisture permeation and hydration reactions, of which the mechanism is studied by density functional theory calculations. Deleterious effects such as thickness reduction over time could be suppressed by applying a protective Al2O3 layer on top of alucone. A preliminary nucleation period was required in the ALD process of Al2O3 films on alucone surfaces, prior to reaching a linear regime where the thickness increases linearly with respect to the number of ALD cycles. The same behavior was observed for alucone growing on Al2O3. The protective Al2O3 films were found to effectively suppress moisture permeation, thus isolating the underlying alucone from the surrounding environment. The water vapor transmission rate was greatly reduced when an Al2O3/alucone/Al2O3 multilayer stack was formed, which suggests that proper combinations of organic/inorganic hybrid structures may provide chemically stable platforms, especially for mechanically flexible applications.
Division of Materials Science and Engineering, Hanyang University , 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Dong-Won
DW
Choi
Department of Materials Science and Engineering, Chungnam National University , 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
Mi
M
Yoo
Department of Materials Science and Engineering, KAIST , 291 Daehak-ro, Yuseong-gu, Yuseong-gu, Daejeon 34141, Republic of Korea.
Hyuck Mo
HM
Lee
Department of Materials Science and Engineering, KAIST , 291 Daehak-ro, Yuseong-gu, Yuseong-gu, Daejeon 34141, Republic of Korea.
Jozeph
J
Park
Department of Materials Science and Engineering, Chungnam National University , 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
Hyun You
HY
Kim
Division of Materials Science and Engineering, Hanyang University , 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Jin-Seong
JS
Park
Al2O3; alucone; atomic layer deposition; density functional theory; diethylene glycol; inorganic/organic structure; molecular layer deposition