Skip to main content

Method to transfer entire 2D circuits to any smooth surface

Method to transfer entire 2D circuits to any smooth surface :
Illustration of flexible, 2-D circuit.
What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.
Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices to report on what they perceive.
Electronically active 2D materials have been the subject of much research since the introduction of graphene in 2004. Even though they are often touted for their strength, they're difficult to move to where they're needed without destroying them.
The Ajayan and Lou groups, along with the lab of Rice engineer Jacob Robinson, have a new way to keep the materials and their associated circuitry, including electrodes, intact as they're moved to curved or other smooth surfaces.
The results of their work appear in the American Chemical Society journal ACS Nano.
The Rice team tested the concept by making a 10-nanometer-thick indium selenide photodetector with gold electrodes and placing it onto an optical fiber. Because it was so close, the near-field sensor effectively coupled with an evanescent field -- the oscillating electromagnetic wave that rides the surface of the fiber -- and accurately detected the flow of information inside.
The benefit is that these sensors can now be imbedded into such fibers where they can monitor performance without adding weight or hindering the signal flow.
"This paper proposes several interesting possibilities for applying 2D devices in real applications," Lou said. "For example, optical fibers at the bottom of the ocean are thousands of miles long, and if there's a problem, it's hard to know where it occurred. If you have these sensors at different locations, you can sense the damage to the fiber."
Lou said labs have gotten good at transferring the growing roster of 2D materials from one surface to another, but the addition of electrodes and other components complicates the process. "Think about a transistor," he said. "It has source, drain and gate electrodes and a dielectric (insulator) on top, and all of these have to be transferred intact. That's a very big challenge, because all of those materials are different."
Raw 2D materials are often moved with a layer of polymethyl methacrylate (PMMA), more commonly known as Plexiglas, on top, and the Rice researchers make use of that technique. But they needed a robust bottom layer that would not only keep the circuit intact during the move but could also be removed before attaching the device to its target. (The PMMA is also removed when the circuit reaches its destination.)
The ideal solution was polydimethylglutarimide (PMGI), which can be used as a device fabrication platform and easily etched away before transfer to the target. "We've spent quite some time to develop this sacrificial layer," Lou said. PMGI appears to work for any 2D material, as the researchers experimented successfully with molybdenum diselenide and other materials as well.
The Rice labs have only developed passive sensors so far, but the researchers believe their technique will make active sensors or devices possible for telecommunication, biosensing, plasmonics and other applications.
Rice graduate student Zehua Jin is lead author of the paper. Co-authors are Rice graduate students Fan Ye, Shuai Jia and Liangliang Dong and postdoctoral researcher Xiang Zhang; Rice alumnus Sidong Lei, now an assistant professor at Georgia State University, and Robert Vajtai, a research professor in materials science and nano engineering at Rice. Ajayan is chair of Rice's Department of Materials Science and Nano Engineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry. Lou is a professor of materials science and nano engineering. Robinson is an assistant professor of electrical and computer engineering.
The research was supported by the Air Force Office of Scientific Research, the Welch Foundation, Rice IDEA and Function Accelerate nano Material Engineering (FAME), one of six centers of the Semiconductor Technology Advanced Research Network sponsored by the Microelectronics Advanced Research Corporation and the Defense Advanced Research Projects Agency.

Comments

Post a Comment

Popular posts from this blog

Home births as safe as hospital births: International study suggests

A large international study led by McMaster University shows that low risk pregnant women who intend to give birth at home have no increased chance of the baby's perinatal or neonatal death compared to other low risk women who intend to give birth in a hospital. The results have been published by  The Lancet 's  EClinicalMedicine  journal. "More women in well-resourced countries are choosing birth at home, but concerns have persisted about their safety," said Eileen Hutton, professor emeritus of obstetrics and gynecology at McMaster, founding director of the McMaster Midwifery Research Centre and first author of the paper. "This research clearly demonstrates the risk is no different when the birth is intended to be at home or in hospital." The study examined the safety of place of birth by reporting on the risk of death at the time of birth or within the first four weeks, and found no clinically important or statistically different risk between home...
Post a Comment
Read more

Dark matter may be older than the Big Bang

Dark matter, which researchers believe make up about 80% of the universe's mass, is one of the most elusive mysteries in modern physics. What exactly it is and how it came to be is a mystery, but a new Johns Hopkins University study now suggests that dark matter may have existed before the Big Bang. The study, published August 7 in  Physical Review Letters , presents a new idea of how dark matter was born and how to identify it with astronomical observations. "The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too," says Tommi Tenkanen, a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study's author. While not much is known about its origins,...
Post a Comment
Read more

Scientists challenge notion of binary sexuality with naming of new plant species

A collaborative team of scientists from the US and Australia has named a new plant species from the remote Outback. Bucknell University biology postdoctoral fellow Angela McDonnell and professor Chris Martine led the description of the plant that had confounded field biologists for decades because of the unusual fluidity of its flower form. The discovery, published in the open access journal  PhytoKeys , offers a powerful example of the diversity of sexual forms found among plants. The new species of bush tomato discovered in remote Australia provides a compelling example of the fact that sexuality among Earth's living creatures is far more diverse -- and interesting -- than many people likely realize. Bucknell University postdoctoral fellow Angela McDonnell and biology professor Chris Martine led the study following an expedition last year to relocate populations of the new plant, which were first noted by Australian botanists during the 1970s. Herbarium specimens from th...
Post a Comment
Read more