Researchers discover method for atomic scale semiconductors

The method can be used to create thin films on a scale large enough to coat wafers that are 2in wide, or larger, which the researchers say could pave the way towards scaled down electronic devices such as leds and transistors. To begin with, the researchers placed sulphur and an inexpensive semiconductor material called molybdenum chloride in a furnace and gradually raised the temperature to 850°C. Once the two substances reacted to form MoS2, the vapour was deposited into a thin layer onto the substrate. The researchers found that they could precisely control the thickness of the MoS2 layer by controlling the partial pressure and vapour pressure in the furnace. "Using this technique, we can create wafer scale MoS2 monolayer thin films, one atom thick, every time," said lead researcher Dr Linyou Cao. "We can also produce layers that are two, three or four atoms thick. Cao's team is now trying to find ways to create similar thin films in which each atomic layer is made of a different material. The researchers are also working to create field effect transistors and leds using the technique.