The next big advance for electronics could be driven by a new technique that uses liquid metals to create integrated circuits that are mere atoms thick.
Large wafers around 1.5 nm in depth could be produced by using this new process. For comparison purposes, a sheet of paper is 100,000 nm thick. Other techniques designed in the past have proven to not be reliable in terms of quality and are difficult to scale up. They also only work properly at temperatures of 550 degrees or more.
Professor Kourosh Kalantar-zadeh from the School of Engineering at RMIT University in Melbourne, Australia, led the project. His team included colleagues from RMIT, as well as researchers from Monash University, CSIRO, the University of California and North Carolina State University.
The professor is of the opinion that the electronics industry has hit a barrier.
He explained that since 1920, the fundamental technology of car engines has not progressed and that the same is now happening to electronics. Computers and mobile phones are no more powerful than five years ago, and that is why this new 2D printing technique is so important. Processing power can be increased dramatically and costs reduced substantially by creating many layers of amazingly thin electronic chips on the same surface.
This will enable the next revolution in electronics.
According to Benjamin Carey, a researcher with the CSIRO and RMIT, the limitations of current chip production could be overcome by creating electronic wafers just atoms thick. It could also pave the way for flexible electronics by producing materials that were extremely malleable.
Carey added that none of the current technologies is able to create uniform surfaces of atomically thin semiconductors on large surface areas. This is a requirement if the chips are to be manufactured on an industrial scale. The team’s solution is to use indium and gallium, both metals with a low melting point. Both these metals produce a layer of oxide on their surface that is atomically thin and protects them naturally. This thin oxide is used in the fabrication method.
The oxide layer can be transferred on to an electronic wafer by rolling the liquid metal. The wafers are then sulphurized. To form individual transistors, the surface of the wafers are pre-treated. The team has used this novel method to create photo detectors and transistors. Both these types of components exhibit a very high gain and are able to be manufactured on a large scale with very high reliability.