Moving Atomically Thin Semiconductors for Use in Flexible Devices
Researchers from North Carolina State University have developed a new way to transfer thin semiconductor films, which are only one atom thick, onto arbitrary substrates - paving the way for flexible computing or photonic devices. The films, called molybdenum sulfide (MoS2), have electronic and optical properties similar to materials already used in the semiconductor industry. MoS2 is hydrophobic – it repels water. But the sapphire substrate the thin film is grown on is hydrophilic – it attracts water. The new transfer technique works by applying a drop of water to the thin film and then poking the edge of the film with tweezers or a scalpel so that the water can begin to penetrate between the MoS2 and the sapphire. Once it has begun to penetrate, the water pushes into the gap, floating the thin film on top. The researchers use a tissue to soak up the water and then lift the thin film with tweezers and place it on a flexible substrate. The whole process takes a couple of minutes. "This new transfer technique gets us one step closer to using MoS2 to create flexible computers," says Dr. Linyou Cao, an assistant professor of materials science and engineering. "We are currently in the process of developing devices that use this technology."