摘要： As the scaling of semiconducting devices in integrated circuits approaches dimensions less than 10 nm, the emphasis for future technologies has moved towards improved energy efficiency and the use of three dimensional (3D) integration schemes to achieve an increased density of devices per unit area. For many of these applications there is a need to explore new semiconducting materials which allow flexibility in electronic and optical properties, and can also be processed at reduced temperatures, which allows their integration above conventional silicon based integrated circuits. One class of materials that demonstrates considerable promise for these emerging applications is van der Waals bonded two dimensional (2D) semiconductors. The study of these 2D layered material systems is not new, with studies dating back to the 1920s and the identification of monolayers and bi-layers of MoS2 in the 1960s. What is particularly exciting about this general class of semiconductors is that they have a range of energy gaps which span from semi-metals through to wide bandgap semiconductors and as a consequence have potential applications in electronic devices, sensors, through to applications in flexible electronics, photovoltaics, and the light emitting diodes.