A unique ‘sandwich‘ of graphene and boron nitride could lead to the next-gen microelectronics creates a good material for use in new technology applications.
Moiré patterns occur everywhere. They are created by joining two similar but not identical geometric shapes. A common example is the pattern that sometimes appears when viewing a link fence from a second link fence.
For more than 10 years, scientists have been experimenting with the moiré pattern that appears when a sheet of graphene is sandwiched between two sheets of boron nitride. The resulting moire pattern has shown dramatic effects that could improve semiconductor chips used in everything from computers to cars.
A new study by researchers at the University of Buffalo published in Nature Communications has shown that graphene can hold its promise in this situation.
“Our recent work shows that this sandwich of graphene and boron nitride creates a good material for use in new technology applications,” said Jonathan Bird, PhD, professor and chair of UB’s Department of Electrical Engineering. said. This research was funded in part by the US Department of Energy and by a MURI grant from the US Army’s Office of Science Research.
Graphene is made of carbon, just like carbon and diamond. What separates graphene is the way carbon atoms are connected: they are connected in a hexagonal or honeycomb pattern. The result is the thinnest object ever known, so thin that scientists call it a biplane.
Left alone, graphene conducts electricity very well – well, in fact, it is useful in microelectronics technology. But by sandwiching graphene between two layers of boron nitride, which also has a hexagonal pattern, a moire pattern is produced. The presence of this principle is accompanied by a dramatic change in the properties of graphene, transforming the material that is normally conducted into a (semiconductor-like) material that can be used in microelectronics is high.
The research shows how the moiré pattern of graphene can be adapted for use in technological applications such as new types of communication devices, lasers and light-emitting diodes. “Our work has demonstrated the effectiveness of this method, showing that the graphene/boron nitride sandwich we are investigating indeed has the properties necessary for microelectronics,” said Bird.
Semiconductor chips are important not only in smartphones and medical devices, but also in smart home appliances such as dishwashers, vacuum cleaners and home security systems. “Modern technology relies on semiconductor chips that form the heart of their systems and control their operations,” Bird said. “When you talk into your phone, it’s a chip that converts your voice into an electronic signal and transmits it to the tower.”
The graphene/boron nitride heterostructure appears to have properties that lend themselves to engineering. The development of future technologies based on these factors may depend on the discovery and exploitation of factors that increase speed and performance. Bird said there is often a time lag between discovery, the excitement of discovery, and the fulfillment of the promise of discovery. Graphene – so common that it can be found in every paper with a pencil – was not discovered until 2004.
Bird earned a doctorate in physics, but was drawn to electrical engineering because it allowed him to explore quantum physics through semiconductor research. Quantum physics – “a kind of magical physics that takes place in atomic quantities”, he explained – can be seen through experiments using technology that examines matter and processes at the atomic level.
“We can make the system react to the actions we take, and the response reflects the details of the atomic and quantum nature of the system,” he said. Graphene caught his eye because it seemed like a way to study quantum effects through semiconductor activity. At UB, he established a laboratory called NoMaD, where he, his colleagues, and their students study “the amazing things that happen at the nanoscale.” Graduates have gone on to work at Intel and IBM as well as other universities.
In this research, Bird and his team investigated the properties of graphene and some of the limitations that must be met in order to develop new technologies. The semiconductor chip industry is a huge industry that continues to grow, looking for new things, new ways to use existing materials, and new users who can create both.
Source: University at Buffalo
