Recently, several of my colleagues at Keithley made a customer visit to the Condensed Matter Physics Lab at the University of Manchester. That visit coincided with the announcement that Drs. Geim and Novoselov had just been awarded the 2010 Nobel Prize in Physics.
In their prize-winning research on graphene, a one-atom-thick layer of carbon atoms densely packed in a honeycomb crystal lattice, they used several Keithley instruments, including the Model 2182A nanovoltmeter and two Model 2400 SourceMeter instruments, to study this material’s field effect properties.
If millions of graphene layers were stacked one on top of the other, the resulting product would be graphite, but the two materials are fundamentally very different. Graphene has a number of unique physical, chemical, and electrical properties.
Unlike graphite, graphene demonstrates not only an electric field effect but also ballistic electronic transport, which results in very high charge carrier mobilities of at least 60,000cm2/Vs. Such mobilities exceed that of silicon by at least a factor of 40, which makes graphene of particular interest to designers of the next generation of fast transistors. Also, much as with carbon nanotubes, the electronic bonds in graphene are very strong, which makes it an excellent structural material.
In the last few months, it seems like everyone has begun talking about the potential for graphene-based materials, which range from use in single-molecule gas detectors and solar cells to DNA sequencing and anti-bacterial materials. From the perspective of electronics manufacturing and test, graphene has highly exploitable electrical properties. For example, graphene sheets have extremely low resistivity at room temperature. When electrons are confined in two-dimensional materials like graphene, it’s also possible to observe transport phenomena such as the quantum Hall effect. Of course, for Keithley and its customers, graphene’s most exciting possibilities are those associated with its potential for the development of new nanoscale devices like nanoribbons, transparent conducting electrodes, transistors, ICs, ultracapacitors, and many others.
So, what does graphene’s potential mean for researchers and the test equipment vendors that serve them? First and foremost, it means that access to high accuracy, high sensitivity instruments and systems that are easy to use and flexible enough to adapt quickly to evolving requirements will be more crucial to researchers than ever before. To keep making progress on the graphene-based materials and devices that may one day replace the silicon-based ones we use now, scientists and researchers will need the support of their vendors to learn how to wring the maximum measurement sensitivity from their existing test hardware. Just as important, test hardware vendors and researchers must learn how to work together effectively to envision and then realize the next generation of high sensitivity instruments.
For access to information on some of the research on graphene now being conducted in labs around the world, visit the Google Scholar search engine at http://scholar.google.com/schhp?hl=en&tab=ws
and enter “graphene” in the search box. Like me, I’m sure you’ll be amazed by the amount and range of research now being conducted. About the author:
Linda Rae is Executive Vice President and Chief Operating Officer at Keithley Instruments, Inc. Rae joined Keithley in 1995 with a position in product marketing and later served as head of Keithley's Component Test Group, as well as the company's Optoelectronics Group, and most recently was the company's Senior Vice President and General Manager.
Rae earned a Bachelor of Science degree in Electrical Engineering from the University of Florida. In addition, she holds a Master of Business Administration from the Weatherhead School of Management at Case Western Reserve University and a Master of Science degree in Electrical Engineering from Case Western Reserve University.
Rae is a former member of the Weatherhead School of Management Alumni Association Board of Directors. As part of Keithley work teams, Rae has received two EDI (NorTech) awards and an internal Keithley QSII (Quality-Service-Innovation-Integrity) award for innovation.