Van der Waals growth of monolayer MoS$_{\mathrm{\mathbf{2}}}$\textbf{ and its heterostructures}

Monolayer MoS$_{\mathrm{2}}$ as one kind of TMDs two-dimensional (2D) crystals, is a direct bandgap semiconductor and has attracted much research interests beyond graphene. We report the van der Waals (vdW) growth of monolayer MoS$_{\mathrm{2}}$ by chemical vapor deposition (CVD) in our developed 3-zones furnace with high quality. The integrated flexible TFTs based on our CVD MoS$_{\mathrm{2}}$ have been fabricated with the device structure compatible with the traditional semiconductor fabrication process. The uniformity of the continuous MoS$_{\mathrm{2}}$ film leads to the stable performance over a centimeter scale even under uniaxial strain 1{\%} with mobilities of 14 cm$^{\mathrm{2}}$v$^{\mathrm{-1}}$s$^{\mathrm{-1}}$ and on/off ratio higher than 10$^{\mathrm{5}}$. The excellent performance of those devices suggests that they are promising candidates for flexible and integrable electronics devices in future. The epitaxial growth of MoS$_{\mathrm{2}}$ on WS$_{\mathrm{2}}$ via a two-step CVD growth approach was also reported to create bilayers of vdW heterostructures with clean interface and strong interlayer coupling. It was demonstrated that our epitaxial growth of MoS$_{\mathrm{2}}$ /WS$_{\mathrm{2}}$ heterostructures has strong interlayer coupling and reveals more efficient interlayer charge transfer and spatially separated exciton recombination than the transferred heterostructures. References: 1. \textbf{Adv. Electron. Mater. }2016, 2: 1500379. 2. \textbf{Adv. Mater.} 2016, 28: 1950. 3. \textbf{J. Am. Chem. Soc. }2015, 137 (50): 15632. 4. \textbf{ACS Nano} 2014, 8: 6024.