Two-Dimensional Meta-Materials

The term meta-materials refers to materials that are created by producing material structures that do not occur in nature and also can be created with structural complexity that also would not occur in nature. Graphene has long been a material of interest. For a long time, the issue with graphene has been the ability to produce it in large areas without any defects. The work done in Reference 1 was focused on evaluating a nano electronics platform based on graphene. The interest is because the technology is compatible with conventional semiconductor manufacturing. This work was based on the results of research that found a layer of graphene formed on the top of silicon carbide crystal. It was discovered that electric currents flow without resistance along the edges of this material plus the graphene devices could be interconnected without metal wires. The researchers observed that the electrons could travel over large distances, microns, without scattering. Previous technologies could only obtain 10 nm before scattering. Their estimates are that it will be up to 10 years before the graphene-based electronics could be realized in volume manufacturing.

A slightly different class of two-dimensional meta-materials is called MXenes. These MXenes are part of a large family of nitrides and carbides of transition materials constructed in two dimensional layers where two or more of the metal layers are interspersed by a carbon or nitrogen layer. This surface is finished off with a termination layer. According to the researchers [Reference 2], these MXenes can be fabricated as nanometer thin flakes that can be better dispersed in water and inked onto any surface. They can also be made as films, fibers and even powders research areas using these materials includes optoelectronics, electromagnetic interference shielding, wireless antennas, total catalyst, water purification, biosensing, and many more. There is also the possibility of using these materials as alternatives to lithium-ion batteries. The issue right now is that this material tends to oxidize and degrade quickly in ambient operating conditions. Removing the oxidation will require some additional inventions. Work done in Australia has found one method to work to remove the oxidation, which focuses a 10 MHz frequency beam, which breaks the bond of the oxidation. Some work in China has use this material as an electrochemical biosensor that is coupled with gold nano arrays to attempt to have a noninvasive cancer detection system. One of the challenges using this material is that there are an extremely large number of possible configurations. Finding the best ones to work with will require significant computational analysis.

Reference 3 looks at a new layering technique for two dimensional materials with the possibility of being able to tune the materials for different applications. One of the findings was that sandwiching atomic layers of a transition metal like titanium between monoatomic layers of another metal, like molybdenum, and using carbon atoms to hold them together.  The researchers discovered that a stable material can be produced. A key result of their work which could be beneficial in the future is that they have found a way to combine elemental materials into a stable compound, which will exhibit new properties. This particular arrangement of atomic structures opens up the possibility to fine tune the resulting molecular structure and its related physical properties to meet certain stringent applications that at the present time cannot be considered.

The development of the atomic layer materials and the ability to manipulate them into ways that produce different characteristics is opening up an entirely new world for researchers to create new, and previously unknown, material properties. This is not something that will happen immediately but the effort is providing a whole new branch of scientific experimentation. It will be interesting to see what the future brings.



About Walt

I have been involved in various aspects of nanotechnology since the late 1970s. My interest in promoting nano-safety began in 2006 and produced a white paper in 2007 explaining the four pillars of nano-safety. I am a technology futurist and is currently focused on nanoelectronics, single digit nanomaterials, and 3D printing at the nanoscale. My experience includes three startups, two of which I founded, 13 years at SEMATECH, where I was a Senior Fellow of the technical staff when I left, and 12 years at General Electric with nine of them on corporate staff. I have a Ph.D. from the University of Texas at Austin, an MBA from James Madison University, and a B.S. in Physics from the Illinois Institute of Technology.
Nanotechnology, Semiconductor Technology

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