news digest ♦ Novel Devices
Yet when associate professor of physics Latika Menon peered under the electron microscope last fall, she discovered the exact opposite. Instead of art imitating nature, she found nature imitating art.
Transmission electron microscope cross-section of the vertical TFET. The interface of the source and channel is the point where electron tunnelling occurs. ILD is the interlayer dielectric separating the contacts. Top plane contacts are Gold (Au), Palladium (Pd), and Molybdenum (Mo). (Image: Suman Datta/Penn State)
The paper, “Demonstration of InGaAs/GaAsSb Near Broken-gap Tunnel FET with Ion=740µA/µm, GM=700µS/µm and Gigahertz Switching Performance at VDS=0.5V,” will be available in the conference proceedings publication of the IEDM.
This device was developed as part of a larger program sponsored by the National Science Foundation through the Nanosystems Engineering Research Centre for Advanced Self-Powered Systems of Integrated Sensors and Technologies (NERC-ASSIST). The broader goal of the ASSIST program is to develop battery-free, body- powered wearable health monitoring systems with Penn State, North Carolina State University, University of Virginia, and Florida International University as participating institutions.
Associate professor Latika Menon and her lab use macroscopic techniques to create nanscopic materials. (Photo by Brooks Canaday)
Menon grew up in the eastern region of India and was vaguely familiar with a cultural dance from the western state of Rajasthan known as the Bhavai pot dance. Nimble dancers sway their hips as a tall stack of wide- bellied pots balances gingerly atop their heads.
Back in the lab at Northeastern, Menon’s team recently created GaN nanowires, which bore a striking resemblance to that stack of pots.
What’s more, a postdoctoral research associate in Menon’s lab, Eugen Panaitescu, jumped on the bandwagon with a cultural art reference of his own. Panaitescu, who hails from Romania, also saw his country’s famous Endless Column reflected in the nanowires.
Dedicated to the fallen Romanian heroes of World War I, Constantin Brancusi’s 96- foot tall monolith is constructed of seventeen three- dimensional rhombuses, periodically wavering from a wider circumference to a narrower one.
Tables turn as nature imitates art
Researchers at Northeastern University have grown GaN nanowires which represent a breakthrough in processing them for these novel uses
There are examples of art imitating nature all around us - whether it’s Monet’s pastel Water Lilies or Chihuly’s glassblown Seaforms, the human conception of natural phenomena dazzles but does not often surprise.
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www.compoundsemiconductor.net January / February 2014
But the Northeastern researchers’ nanowires aren’t just notable for their aesthetic appeal. GaN is used across a range of technologies, including most ubiquitously in LEDs. The material also holds great potential for solar cell arrays, magnetic semiconductors, high- frequency communication devices, and many other things. But these advanced applications are restricted by our limited ability to control the material’s growth on the nanoscale.
The very thing that makes Menon’s nanowires beautiful represents a breakthrough in her ability to process them for these novel uses. She deposited onto a silicon substrate small droplets of liquid gold metal, which act as catalysts to grab gaseous GaN from the atmosphere of the experimental system.
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