University at Buffalo - The State University of New York

Published: March 1, 2007

KEVIN FRYLING
Reporter Staff Writer

The prevailing theory regarding the technology of tomorrow is to think small.

Yong-Kyu (YK) Yoon says that fast, affordable and reliable methods to mass-produce intricate micro- and nanoscale structures are required to develop future technologies.
PHOTO: NANCY J. PARISI

That observation comes from a UB expert in micro- and nanoscale electronics, who points out that everything from consumer electronics to the tools that diagnose disease is shrinking as science unlocks the secrets of the microscopic—as well as nanoscopic—world.

"People want to scale down from big to smaller and smaller," says Yong-Kyu (YK) Yoon, assistant professor in the Department of Electrical Engineering, School of Engineering and Applied Sciences, who joined the faculty last fall. "In the last decade, nanotechnology has grown up fast."

The highly multidisciplinary research topics in which Yoon is engaged—a checklist of leading-edge subjects that includes microwave engineering, 3-D MEMS (Micro-Electro-Machine System) fabrication, bio- microfluidics, optic devices, sensors and actuators and nanomaterials—all come together through his role as founder and director of the new Multidisciplinary nano and Microsystems (MnM) Lab in Bonner Hall on the North Campus.

Yoon says these subjects fascinate him because there is so much that remains to be discovered in an emerging field that still is often looked upon as being a "black box." He says that neither the efforts of engineers to build micro- or nanostructures from the "top down" nor chemists and physicists to develop them from the "bottom up" on a molecular level have met complete success.

He points to a project in his lab that involves a complicated twist on a process known as UV lithography—a standard industrial technique that uses photosensitive polymers to fabricate flat structures, such as the integrated circuits in microchips, to produce three-dimensional microscale components that are used in microwave engineering. He says that fast, affordable and reliable methods to mass-produce intricate micro- and nanoscale structures are required to speed progress towards future technologies.

Hundreds of thousands of "cone antennas," "micronozzles" and other small-scale components that are created in his lab are required to build wireless devices that utilize short and powerful "millimeter waves," he explains.

"I'm dealing with the millimeter waves, of which their characteristic length is in the 1-to-10 millimeter scale, corresponding to the frequency range 30 to 300 gigahertz," says Yoon, a specialist in radiofrequency (RF) electronics. Cell phones and other consumer wireless devices that currently operate at one or two gigahertz are expected to turn to significantly higher frequencies in the near future. Stronger signals and less interference are two major advantages to millimeter waves, he adds.

Additional applications range from bio-imaging and hidden-object detection to airborne cloud radar and radio astronomy. "Millimeter waves penetrate through fog, or clothes, or paper, but don't pass through the body," Yoon says.

He also notes that the mass-production of microstructures is required to build microfluidic systems, such as "lab-on-a-chip devices" that "scale a room-sized lab onto a small [handheld] chip."

"Conventionally," says Yoon, "you go to a lab and people take your blood and put it in several syringes and apply it one-by-one by hand. It takes time and effort, and a large amount of blood." A lab-on-a-chip designed to detect disease is different, he notes, because a single drop of blood is filtered through hundreds of thousands of "well-organized" microchannels to "automatically diagnose whether you're sick."

Yoon's knowledge of the biomedical applications of microstructures traces back to his time as a graduate research assistant and postdoctoral fellow from 2004-06 at the Georgia Institute of Technology. While there, he was a participant in a $400,000 transdermal "smart patch" project that sought to enable medication such as insulin to pass straight into the bloodstream through invisible "micropores" created in the skin. Other research in which Yoon was involved at Georgia Tech included a project on micropower electronics, which resulted in a patent for a method to manufacture smaller power inductors, an essential element of components like the adaptors on most laptop cords.

In addition to a doctorate in electrical and computer engineering from Georgia Tech, Yoon holds a master's degree from the New Jersey Institute of Technology and master's and bachelor's degrees from Seoul National University.

Last month, he returned to his alma mater to recruit students to join his UB research lab. "We can recruit very high-quality people from all over the world," Yoon notes, pointing out that UB is ranked number 10 in international enrollment in the United States. "I wish to set up a strong MEMS, or microsystems program, at UB," he adds. "That is my mission." Six graduate and doctoral students now conduct research in the MnM Lab, plus an exchange student who is due to arrive soon from France.

While in Korea last month, Yoon also traveled to three other top-ranked Korean universities. He notes one visit came at the request of a UB alumnus who directs a high-tech radiofrequency integrated circuit (RFIC) center at Kwangwoon University.

Back in Buffalo, Yoon continues to settle into his new home in Williamsville and notes that one of the best things about living in Western New York is that two of his sisters—he is the youngest of eight siblings—live within a short flight of the region. A native of a large, temperate port city in southern Korea, he admits, however, that the Western New York weather has required a bit of an adjustment. "I have never lived in an area with a lot of snow," laughs Yoon, "My hometown is Masan...a very warm place and a beautiful place."

But he is used to cool temperatures from time spent hiking in the mountainous terrain outside Seoul. "In Korea, most of the [Buddhist] temples are in the mountains," says Yoon, "If you hiked, you could visit temples and refresh your spirit, as well as your body."

The visit to UB of His Holiness the 14th Dalai Lama last semester was a highlight of his time thus far at UB, he adds, because he was able to attend the Dalai Lama's lecture with his mother, a devout Buddhist, who flew in to town from Korea for the event.