Characterization of Rotational Stacking Layers in Large-Area MoSe 2 Film Grown by Molecular Beam Epitaxy and Interaction with Photon

Yoon Ho Choi, Dong Hyeok Lim, Jae Hun Jeong, Dambi Park, Kwang Sik Jeong, Minju Kim, Aeran Song, Hee Suk Chung, Kwun Bum Chung, Yeonjin Yi, Mann-Ho Cho

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Abstract

Transition metal dichalcogenides (TMDCs) are promising next-generation materials for optoelectronic devices because, at subnanometer thicknesses, they have a transparency, flexibility, and band gap in the near-infrared to visible light range. In this study, we examined continuous, large-area MoSe 2 film, grown by molecular beam epitaxy on an amorphous SiO 2 /Si substrate, which facilitated direct device fabrication without exfoliation. Spectroscopic measurements were implemented to verify the formation of a homogeneous MoSe 2 film by performing mapping on the micrometer scale and measurements at multiple positions. The crystalline structure of the film showed hexagonal (2H) rotationally stacked layers. The local strain at the grain boundaries was mapped using a geometric phase analysis, which showed a higher strain for a 30° twist angle compared to a 13° angle. Furthermore, the photon-matter interaction for the rotational stacking structures was investigated as a function of the number of layers using spectroscopic ellipsometry. The optical band gap for the grown MoSe 2 was in the near-infrared range, 1.24-1.39 eV. As the film thickness increased, the band gap energy decreased. The atomically controlled thin MoSe 2 showed promise for application to nanoelectronics, photodetectors, light emitting diodes, and valleytronics.

Original languageEnglish
Pages (from-to)30786-30796
Number of pages11
JournalACS Applied Materials and Interfaces
Volume9
Issue number36
DOIs
Publication statusPublished - 2017 Sep 13

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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