title: Highly stable 2D material (2DM) field-effect transistors (FETs) with wafer-scale multidyad encapsulation.
abstract: Field-effect transistors (FETs) composed of 2D materials (2DMs) such as transition-metal dichalcogenide (TMD) materials show unstable electrical characteristics in ambient air due to the high sensitivity of 2DMs to water adsorbates. In this work, in order to demonstrate the long-term retention of electrical characteristics of a TMD FET, a multidyad encapsulation method was applied to a MoS2FET and thereby its durability was warranted for one month. It was well known that the multidyad encapsulation method was effective to mitigate high sensitivity to ambient air in light-emitting diodes (LEDs) composed of organic materials. However, there was no attempt to check the feasibility of such a multidyad encapsulation method for 2DM FETs. It is timely to investigate the water vapor transmission ratio (WVTR) required for long-term stability of 2DM FETs. The 2DM FETs were fabricated with MoS2flakes by both an exfoliation method, that is desirable to attain high quality film, and a chemical vapor deposition (CVD) method, that is applicable to fabrication for a large-sized substrate. In order to eliminate other unwanted variables, the MoS2FETs composed of exfoliated flakes were primarily investigated to assure the effectiveness of the encapsulation method. The encapsulation method uses multiple dyads comprised of a polymer layer by spin coating and an Al2O3layer deposited by atomic layer deposition (ALD). The proposed method shows wafer-scale uniformity, high transparency, and protective barrier properties against adsorbates (WVTR of 8 × 10-6g m-2day-1) over one month.
authors.affiliation: School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Choong-Ki
authors.initials: CK
authors.lastname: Kim
authors.forename: Eun Gyo
authors.initials: EG
authors.lastname: Jeong
authors.forename: Eungtaek
authors.initials: E
authors.lastname: Kim
authors.forename: Jeong-Gyu
authors.initials: JG
authors.lastname: Song
authors.forename: Youngjun
authors.initials: Y
authors.lastname: Kim
authors.forename: Whang Je
authors.initials: WJ
authors.lastname: Woo
authors.forename: Myung Keun
authors.initials: MK
authors.lastname: Lee
authors.forename: Hagyoul
authors.initials: H
authors.lastname: Bae
authors.forename: Seong-Bae
authors.initials: SB
authors.lastname: Jeon
authors.forename: Hyungjun
authors.initials: H
authors.lastname: Kim
authors.forename: Kyung Cheol
authors.initials: KC
authors.lastname: Choi
authors.forename: Yang-Kyu
authors.initials: YK
authors.lastname: Choi