Wafer Scale Synthesis and High Resolution Structural Characterization of Atomically Thin MoS2 Layers

• Published in: Advanced functional materials 2014-12, Vol.24 (47), p.7461-7466
• Main Authors: George, Aaron S., Mutlu, Zafer, Ionescu, Robert, Wu, Ryan J., Jeong, Jong S., Bay, Hamed H., Chai, Yu, Mkhoyan, K. Andre, Ozkan, Mihrimah, Ozkan, Cengiz S.
• Format: Article
• Language: English
• Subjects: alloys; HAADF-STEM; MoS2; transition-metal dichalcogenides; WS2
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201402519

Synthesis of atomically thin MoS2 layers and its derivatives with large‐area uniformity is an essential step to exploit the advanced properties of MoS2 for their possible applications in electronic and optoelectronic devices. In this work, a facile method is reported for the continuous synthesis of atomically thin MoS2 layers at wafer scale through thermolysis of a spin coated‐ammonium tetrathiomolybdate film. The thickness and surface morphology of the sheets are characterized by atomic force microscopy. The optical properties are studied by UV–Visible absorption, Raman and photoluminescence spectroscopies. The compositional analysis of the layers is done by X‐ray photo­emission spectroscopy. The atomic structure and morphology of the grains in the polycrystalline MoS2 atomic layers are examined by high‐angle annular dark‐field scanning transmission electron microscopy. The electron mobilities of the sheets are evaluated using back‐gate field‐effect transistor configuration. The results indicate that this facile method is a promising approach to synthesize MoS2 thin films at the wafer scale and can also be applied to synthesis of WS2 and hybrid MoS2‐WS2 thin layers. Wafer scale synthesis of atomically thin MoS2 layers via thermolysis of spin coated films is presented. High resolution characterization of atomically thin layers is performed by HAADF‐STEM image analysis. This approach could be applied to a variety of substrates and provides a promising route towards wafer scale production of other TMD and doped materials for applications in electronics and optoelectronics.