Atomic layer deposition of Al2O3 on MoS2, WS2, WSe2, and h-BN: surface coverage and adsorption energy. Issue 2 (4th January 2017)

• Record Type: Journal Article
• Authors: Park, Taejin; Kim, Hoijoon; Leem, Mirine; Ahn, Wonsik; Choi, Seongheum; Kim, Jinbum; Uh, Joon; Kwon, Keewon; Jeong, Seong-Jun; Park, Seongjun; Kim, Yunseok; Kim, Hyoungsub
• Is Part Of: RSC advances. Volume 7:Issue 2(2017)
• Page Start: 884
• Page End: 889
• Publication Date: 2017-01-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra24733d
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The adsorption energies of trimethyl-aluminum on 2D crystals are extracted by quantifying the surface coverage of Al2 O3 grown by atomic layer deposition. Abstract : Uniform deposition of high- k dielectrics on two-dimensional (2D) crystals is highly desirable for their use in future nano-electronic devices. Here, the surface coverage of the Al2 O3 films grown by atomic layer deposition (ALD) was investigated on mechanically-exfoliated MoS2, WS2, WSe2, and h-BN flakes for exploring the deposition kinetics of the Al2 O3 films on the 2D crystals. The film coverage followed a decreasing order of WSe2 > WS2 > MoS2 > h-BN, which was mainly determined by the ALD temperature and adsorption energy ( E ads ) of the ALD precursor (trimethyl-aluminum) during the initial ALD cycles. The obtained | E ads | values of the precursor on the 2D crystals corresponded well to a van der Waals physisorption energy of 0.05–0.26 eV. Furthermore, the magnitude of the extracted E ads values showed a strong dependence on the induced dipole polarizability of the 2D crystals. The obtained results demonstrate that the surface coverage of the ALD high- k dielectrics can be modulated by choosing the types of the 2D substrates, and could provide a pathway for the integration of high- k dielectrics in 2D crystal-based nano-electronic devices.