Direct Observation of Monolayer MoS2 Prepared by CVD Using In-Situ Differential Reflectance Spectroscopy

Yina Wang; Lei Zhang; Chenhui Su; Hang Xiao; Shanshan Lv; Faye Zhang; Qingmei Sui; Lei Jia; Mingshun Jiang

doi:10.3390/nano9111640

Direct Observation of Monolayer MoS₂ Prepared by CVD Using In-Situ Differential Reflectance Spectroscopy

Nanomaterials (Basel). 2019 Nov 19;9(11):1640. doi: 10.3390/nano9111640.

Authors

Yina Wang¹, Lei Zhang¹, Chenhui Su¹, Hang Xiao¹, Shanshan Lv², Faye Zhang¹, Qingmei Sui¹, Lei Jia^{1

2}, Mingshun Jiang¹

Affiliations

¹ School of Control Science and Engineering, Shandong University, Jinan 250061, China.
² Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China.

Abstract

The in-situ observation is of great significance to the study of the growth mechanism and controllability of two-dimensional transition metal dichalcogenides (TMDCs). Here, the differential reflectance spectroscopy (DRS) was performed to monitor the growth of molybdenum disulfide (MoS₂) on a SiO₂/Si substrate prepared by chemical vapor deposition (CVD). A home-built in-situ DRS setup was applied to monitor the growth of MoS₂ in-situ. The formation and evolution of monolayer MoS₂ are revealed by differential reflectance (DR) spectra. The morphology, vibration mode, absorption characteristics and thickness of monolayer MoS₂ have been confirmed by optical microscopy, Raman spectroscopy, ex-situ DR spectra, and atomic force microscopy (AFM) respectively. The results demonstrated that DRS was a powerful tool for in-situ observations and has great potential for growth mechanism and controllability of TMDCs prepared by CVD. To the best of the authors' knowledge, it was the first report in which the CVD growth of two-dimensional TMDCs has been investigated in-situ by reflectance spectroscopy.

Keywords: chemical vapor deposition; in-situ differential reflectance spectroscopy; transition metal dichalcogenides.