See-Through Electronics Will Enable a New Generation of Devices
When OSU Electrical Engineering professor John Wager talks about his research, you can hear excitement edging his voice. No wonder. He’s in the position every researcher dreams about: standing on the threshold of a breakthrough that could revolutionize an entire industry—in this case, the electronics industry.
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“I think we’re onto something huge here at Oregon State,” Wager says. “And other people are beginning to sense that now.”
The term “huge” doesn’t exactly fit Wager’s research, because he and his team of graduate students are working at the molecular level, and the end result is, well—invisible. But that’s the ultimate goal: electronics that are so crystal clear you can see right through them. Which makes any transparent surface a potential location for electronic devices. And that’s indeed huge.
In 2003, working closely with OSU professors Doug Keszler (chemistry) and Janet Tate (physics), Wager’s group developed the world’s first transparent transistor (the transistor is the most fundamental electronic component). This year, Wager and his multidisciplinary team developed the world’s first simple integrated circuit (a ring oscillator) that will also be transparent.
“When we do that, I think people will realize this technology is ready for prime time,” Wager says with a smile.
Already Wager’s work is drawing the attention of prestigious research journals and major news media: Nature, NPR’s Science Friday, CNN, the journal Science, Wired Magazine, and others.
How did Wager, who’s been at OSU for 21 years, arrive at this research breakthrough? Ever modest, Wager is quick to credit his graduate students, his OSU collaborators, his development engineer, Chris Tasker, and a good dose of luck.
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“You get lucky every once in a while,” he says. “We were trying to figure out how to get electrons to move through various combinations of chemicals to direct electricity in electronic applications and were just in the right place at the right time asking the right questions. I also have great graduate students, and Chris Tasker—he’s the brains behind our entire lab.”
It is within Wager’s sprawling fourth floor lab that materials science, chemistry, physics, electrical engineering, and perseverance converged to help his team discover that common and cheap materials, zinc oxide and tin oxide, could be used to create transparent thin film transistors. They then combined these two elements and discovered that a new material, Zinc Tin Oxide (ZTO), had even greater electrical properties, including much higher electron mobility.
“We just stumbled onto this new material, and although zinc tin oxide is an amorphous structure, its electrical mobility is quite good,” Wager says, ticking off a list of other attributes: very robust (scratch resistant), high chemical stability (facilitates etching), low cost, and a smooth surface. The surface smoothness, he says, is “very, very nice from a manufacturing point of view.” Traditionally, silicon has been used for electronics because its crystalline structure facilitates efficient electron flow.
But silicon requires high temperatures to produce, is too expensive for large-area and low-cost applications, is highly brittle, and is anything but transparent.
Wager’s team has discovered that zinc tin oxide is not the only material that works well for this type of electronics. “We’ve found a sweet spot in the periodic table,” he says. “Which points to a new class of electronic materials.” His group is currently working with zinc indium oxide, another member of this new materials class.
Unlike silicon, these new materials can be produced at very low temperatures and are also flexible, making them applicable to glass, plastics, and bendable materials, such as maps and foils.
Wager’s work could dramatically impact organic light emitting devices, leading to displays that are brighter, crisper, and consume less power. “Our materials might be the solution to the electronic back-plane driver challenge of this projected $10-15 billion market,” he says.
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Solar cell technology would also be improved, as well as a myriad of other applications ranging from security and safety to energy independence.
For example, the infrared or optical transparency of a coating on the window of a home or office could be electronically controlled, to let in more or less heat and light, depending on the weather. A warning could flash inside a car’s windshield glass if sensors detect an object in the street ahead. Invisible burglar alarms could be placed on glass. Printers and copy machines could have electronics applied on the glass, dramatically reducing their overall size.
“As soon as you start letting your mind wander, there are a lot of potential applications out there,” Wager says. But his job, he says, is to develop the basic materials and device technology, for which he currently has six patents pending, and then let private industry incorporate this technology into new devices and products.
Wager’s team has just inked an exclusive licensing agreement with Hewlett-Packard Co. and is working with the Oregon Nanoscience and Microtechnologies Institute (ONAMI) to help commercialize the OSU research.
What else could Wager wish for at this point in his career? He’d like to secure funding to hire another faculty member with expertise in his research area.
This would speed development of his “invisible” research, which is already casting a growing shadow across the electronics industry.
