Editor’s note: This article is by IBM Research Staff Member and Master Inventor Dr. Jeehwan Kim
|Dr. Jeehwan Kim|
Graphene holds incredible promise as a linchpin material for breakthroughs in numerous technologies, and my team at IBM’s Thomas J. Watson Research Center is working to make its potential a reality. Due to its incredible strength and supreme electrical, optical and mechanical properties, graphene – pure carbon functional at the thickness of one atom – has been touted as the next big thing in everything from high-frequency transistors and photo-detectors, to flexible electronics and biosensors. IBM is investing $3B over the next five years towards initiatives such as this, which are building a bridge to a “post-silicon” era.
Part of what makes the material so promising is its strength relative to thickness. At only .3 to .4 nanometers thick (that’s 60,000 times thinner than a sheet of plastic wrap, or 1,000,000 times thinner than a strand of human hair), graphene is an astonishing 200 times stronger than steel. It is also the world’s most conductive material yet discovered, extraordinarily flexible and – as a single layer of carbon atoms – the first two-dimensional material.
Graphene’s periodic hexagonal crystal structure then allowed us to experiment with growing other semiconductor materials that demonstrate similar structural properties. Previously, production of single-crystalline semiconductor films required the use of ~1 millimeter-thick, single-crystalline wafer templates that were not reusable and were very expensive. For example, growth of a 4-inch, wafer-scale GaN (gallium nitride, a direct bandgap semiconductor) film would require a 4-inch SiC wafer – at the cost of some $3000. Now, graphene can be produced in a lab to replace the expensive SiC wafer.
Furthermore, the new growth technique is useful in that semiconductor devices can be deposited on graphene and released or transferred to a flexible substrate.
While we have demonstrated an important, present-day use for this material, the future of graphene as a standalone material is still bright. Uses for graphene are being developed for a number of electronics, and over the next five years, the material could be used as transparent electrodes for touch screen devices, rollable e-paper and foldable LEDs. In the near future, uses are being developed for large-area graphene in high-frequency transistors, logic transistors/thin-film transistors and beyond. Its high electronic mobility – the ability of charged particles to move through a medium in response to an electronic field – makes graphene a promising material.