Nanomaterials could be the foundation for many new technologies, including extremely tiny, flexible and transparent electronics.
While many nanomaterials have promising electronic properties, scientists and engineers are still working to optimally connect these materials together to eventually make semiconductors and circuits with them.
Researchers from Northwestern Engineering have produced two-dimensional (2D) heterostructures from two of these materials, graphene and borophen thereby taking an important step towards integrated circuits from these nanomaterials.
"If you were to break an integrated circuit in a smartphone, many different materials would be integrated together," said Mark Hersam, Walter P. Murphy Professor of Materials Science and Engineering, who led the research. "However, we have reached the limits of many of these traditional materials. The integration of nanomaterials such as borophen and graphene opens up new possibilities in nanoelectronics.
The results were published in the journal with the support of the Office for Naval Research and the National Science Foundation on October 11, 2019. Advances in science . In addition to Hersam, PhD student in applied physics, Xiaolong Liu, co-authored this work.
Creating a New Type of Heterostructure
Each integrated circuit contains many materials that perform different functions, such as: As the conduction of electricity or the isolation of components. Although transistors in circuits have become smaller and smaller, thanks to advances in materials and manufacturing, they are reaching almost the limit of their possible smallness.
Ultrathin 2D materials such as graphene can handle this problem, however, assembling 2D materials is difficult. These materials are only one atom thick. If the atoms of the two materials do not match perfectly, successful integration is unlikely. Unfortunately, most 2D materials do not match at the atomic level, which is a challenge for 2D integrated circuits.
Borophen, the 2D version of boron that Hersam and co-workers first synthesized in 2015, is polymorphic and can therefore take many forms to structure and adapt to its environment. This makes it an ideal candidate for combining with other 2D materials such as graphene.
To test whether it is possible to integrate the two materials into a single heterostructure, Hersam's lab allowed both graphene and borophen to grow on the same substrate. They first grew the graphene because it grows at a higher temperature, then they deposited boron on the same substrate and allowed it to grow in regions where there was no graphene. This process resulted in lateral interfaces where the two materials were sutured together on the atomic scale due to Borophen adaptability.
Measurement of electronic transitions
The laboratory characterized the 2D heterostructure with a scanning tunneling microscope and found the electronic transition The interface was exceptionally abrupt, which means that it is ideally suited to the creation of tiny electronic devices.
"These results suggest that we can create ultra-high density devices on the road," Hersam said. Ultimately, Hersam hopes to achieve ever more complex 2D structures that lead to novel electronic devices and circuits. He and his team are working with Borophen to create additional heterostructures and combine them with an increasing number of hundreds of known 2D materials.
"he said," Two-dimensional materials have the potential to make the next leap. "
Reference:" Borophen Graphene Heterostructures "by Xiaolong Liu and Mark C. Hersam, October 11, 2019, Science Advances .
] DOI: 10.1126 / sciadv.aax6444