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|
| Type |
Poster Presentation |
| Area |
Physical Chemistry |
| Room No. |
Grand Ballroom |
| Time |
10월 19일 (금요일) 11:00~12:30 |
| Code |
PHYS.P-194 |
| Subject |
Varying anisotropy in thermal oxidation of two-dimensional transition metal dichalcogenides |
| Authors |
Myeong in Song, Sunmin Ryu1,*
Department of Chemistry, Pohang University of Science and Technology, Korea
1Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology, Korea
|
| Abstract |
In-plane anisotropy in various material properties of two-dimensional (2D) crystals is not only intriguing but also of potential use for many applications. In this work, we studied how the structural anisotropy influence oxidation of 2D semiconducting transition metal dichalcogenides (TMDs) in the form of MX2, where M = Mo and W; X = S and Se. Single and few-layer TMD samples mechanically exfoliated on SiO2/Si substrates were characterized for thickness by their differential reflectance and thermally oxidized in controlled Ar: O2 mixture at elevated temperatures of 280 ~ 380 oC. Oxidation was initiated from randomly distributed reaction centers and led to triangular oxides (TOs) and triangular etch pits (TEs) that were revealed by atomic force microscopy (AFM) measurements. The TOs and TEs in WX2 were more rounded than those in MoX2 indicating more anisotropic reactions occur in the latter. In addition, the density of TOs and TEs was 30 times higher in MSe2 than MS2, which suggests that MSe2 contains more reaction centers, possibly structural defects. Finally, MoSe2 and WS2 showed the lowest and highest reaction barriers, respectively, which will also be discussed with the observation that only WS2 did not exhibit etch pits. |
| E-mail |
myeonginsong@postech.ac.kr |
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122nd General Meeting of the KCS