Tag Archives: Richard Cairney

University of Alberta team may open door to flexible electronics with engineering breakthrough

There’s some exciting news from the University of Alberta. It emerges from a team that has reconsidered transistor architecture, from a Feb. 9, 2016 news item on ScienceDaily,

An engineering research team at the University of Alberta has invented a new transistor that could revolutionize thin-film electronic devices.

The team was exploring new uses for thin film transistors (TFT), which are most commonly found in low-power, low-frequency devices like the display screen you’re reading from now. Efforts by researchers and the consumer electronics industry to improve the performance of the transistors have been slowed by the challenges of developing new materials or slowly improving existing ones for use in traditional thin film transistor architecture, known technically as the metal oxide semiconductor field effect transistor (MOSFET).

But the U of A electrical engineering team did a run-around on the problem. Instead of developing new materials, the researchers improved performance by designing a new transistor architecture that takes advantage of a bipolar action. In other words, instead of using one type of charge carrier, as most thin film transistors do, it uses electrons and the absence of electrons (referred to as “holes”) to contribute to electrical output. Their first breakthrough was forming an ‘inversion’ hole layer in a ‘wide-bandgap’ semiconductor, which has been a great challenge in the solid-state electronics field.

A Feb. 9, 2016 University of Alberta news release by Richard Cairney and Grecia Pacheco (also on EurekAlert), which originated the news item, provides more detail about the research,

Once this was achieved, “we were able to construct a unique combination of semiconductor and insulating layers that allowed us to inject “holes” at the MOS interface,” said Gem Shoute, a PhD student in the Department of Electrical and Computer Engineering who is lead author on the article. Adding holes at the interface increased the chances of an electron “tunneling” across a dielectric barrier. Through this phenomenon, a type of quantum tunnelling, “we were finally able to achieve a transistor that behaves like a bipolar transistor.”

“It’s actually the best performing [TFT] device of its kind–ever,” said materials engineering professor Ken Cadien, a co-author on the paper. “This kind of device is normally limited by the non-crystalline nature of the material that they are made of”

The dimension of the device itself can be scaled with ease in order to improve performance and keep up with the need of miniaturization, an advantage that modern TFTs lack. The transistor has power-handling capabilities at least 10 times greater than commercially produced thin film transistors.

Electrical engineering professor Doug Barlage, who is Shoute’s PhD supervisor and one of the paper’s lead authors, says his group was determined to try new approaches and break new ground. He says the team knew it could produce a high-power thin film transistor–it was just a matter of finding out how.

“Our goal was to make a thin film transistor with the highest power handling and switching speed possible. Not many people want to look into that, but the raw properties of the film indicated dramatic performance increase was within reach,” he said. “The high quality sub 30 nanometre (a human hair is 50,000 nanometres wide) layers of materials produced by Professor Cadien’s group enabled us to successfully try these difficult concepts”

In the end, the team took advantage of the very phenomena other researchers considered roadblocks.

“Usually tunnelling current is considered a bad thing in MOSFETs and it contributes to unnecessary loss of power, which manifests as heat,” explained Shoute. “What we’ve done is build a transistor that considers tunnelling current a benefit.”

Here’s a link to and a citation for the paper,

Sustained hole inversion layer in a wide-bandgap metal-oxide semiconductor with enhanced tunnel current by Gem Shoute, Amir Afshar, Triratna Muneshwar, Kenneth Cadien, & Douglas Barlage. Nature Communications 7, Article number: 10632 doi:10.1038/ncomms10632 Published 04 February 2016

This is an open access paper.

ETA Feb. 12, 2016: Dexter Johnson has written up the research in a Feb. 11, 2016 posting (on this Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers) where he offers enthusiam (rare) and additional explanation.

Nanoscale light confinement without metal (photonic circuits) at the University of Alberta (Canada)

To be more accurate, this is a step forward towards photonic circuits according to an Aug. 20, 2014 news item on Azonano,

The invention of fibre optics revolutionized the way we share information, allowing us to transmit data at volumes and speeds we’d only previously dreamed of. Now, electrical engineering researchers at the University of Alberta are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips.

This could result in radical increases in computing speeds and reduced energy use by electronic devices.

“We’re already transmitting data from continent to continent using fibre optics, but the killer application is using this inside chips for interconnects—that is the Holy Grail,” says Zubin Jacob, an electrical engineering professor leading the research. “What we’ve done is come up with a fundamentally new way of confining light to the nano scale.”

At present, the diameter of fibre optic cables is limited to about one thousandth of a millimetre. Cables designed by graduate student Saman Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on computer chips. (To put that into perspective, a dime is about one millimetre thick.)

An Aug. 19, 2014 University of Alberta news release by Richard Cairney (also on EurekAlert), which originated the news item, provides more technical detail and information about funding,

 Jahani and Jacob have used metamaterials to redefine the textbook phenomenon of total internal reflection, discovered 400 years ago by German scientist Johannes Kepler while working on telescopes.

Researchers around the world have been stymied in their efforts to develop effective fibre optics at smaller sizes. One popular solution has been reflective metallic claddings that keep light waves inside the cables. But the biggest hurdle is increased temperatures: metal causes problems after a certain point.

“If you use metal, a lot of light gets converted to heat. That has been the major stumbling block. Light gets converted to heat and the information literally burns up—it’s lost.”

Jacob and Jahani have designed a new, non-metallic metamaterial that enables them to “compress” and contain light waves in the smaller cables without creating heat, slowing the signal or losing data. …

The team’s research is funded by the Natural Sciences and Engineering Research Council of Canada and the Helmholtz-Alberta Initiative.

Jacob and Jahani are now building the metamaterials on a silicon chip to outperform current light confining strategies used in industry.

Given that this work is being performed at the nanoscale and these scientists are located within the Canadian university which houses Canada’s National Institute of Nanotechnology (NINT), the absence of any mention of the NINT comes as a surprise (more about this organization after the link to the researchers’ paper).

Here’s a link to and a citation for the paper,

Transparent subdiffraction optics: nanoscale light confinement without metal by Saman Jahani and Zubin Jacob. Optica, Vol. 1, Issue 2, pp. 96-100 (2014) http://dx.doi.org/10.1364/OPTICA.1.000096

This paper is open access.

In a search for the NINT’s website I found this summary at the University of Alberta’s NINT webpage,

The National Institute for Nanotechnology (NINT) was established in 2001 and is operated as a partnership between the National Research Council and the University of Alberta. Many NINT researchers are affiliated with both the National Research Council and University of Alberta.

NINT is a unique, integrated, multidisciplinary institute involving researchers from fields such as physics, chemistry, engineering, biology, informatics, pharmacy, and medicine. The main focus of the research being done at NINT is the integration of nano-scale devices and materials into complex nanosystems that can be put to practical use. Nanotechnology is a relatively new field of research, so people at NINT are working to discover “design rules” for nanotechnology and to develop platforms for building nanosystems and materials that can be constructed and programmed for a particular application. NINT aims to increase knowledge and support innovation in the area of nanotechnology, as well as to create work that will have long-term relevance and value for Alberta and Canada.

The University of Alberta’s NINT webpage also offers a link to the NINT’s latest rebranded website, The failure to mention the NINT gets more curious when looking at a description of NINT’s programmes one of which is hybrid nanoelectronics (Note: A link has been removed),

Hybrid NanoElectronics provide revolutionary electronic functions that may be utilized by industry through creating circuits that operate using mechanisms unique to the nanoscale. This may include functions that are not possible with conventional circuitry to provide smaller, faster and more energy-efficient components, and extend the development of electronics beyond the end of the roadmap.

After looking at a list of the researchers affiliated with the NINT, it’s apparent that neither Jahani or Jacob are part of that team. Perhaps they have preferred to work independently of the NINT ,which is one of the Canada National Research Council’s institutes.

University of Alberta (Canada) student nanorobotics team demonstrates potential medical technology in competitiion

A University of Alberta (Canada) nanorobotics team has entered its nanobot system into the International Mobile Micro/nanorobotics Competition in Karlsruhe, Germany, as part of the ICRA Robot Challenges at the IEEE (Institute of Electrical and Electronics Engineers) International Conference on Robotics and Automation (ICRA) being held May 6 – 10, 2013 in Karlsruhe, Germany. From the May 6, 2013 news item on Nanowerk,

A team of engineering students is putting a twist on robotics, developing a nano-scale robotics system that could lead to new medical therapies.

In less than a year, the U of A team has assembled a working system that manipulates nano-scale ‘robots’. The team uses magnets to manipulate a droplet filled with iron oxide nanoparticles. Barely visible to the naked eye, the droplet measures 400-500 micrometres.

The May 3, 2013 University of Alberta news release by Richard Cairney, which originated the news item, describes the system,

Using a joystick, team members control the robot, making it travel along a specific route, navigate an obstacle course or to push micro-sized objects from one point to another.

The challenge is simple in concept but highly technical and challenging to execute: the team first injects a water droplet with iron oxide nanoparticles into into oil. The droplet holds its shape because it is encased in a surfactant—a soap-like formula that repels water on one side and attracts water on the other.

“It’s like a capsule,” said team member Yang Gao, who is working on her master’s degree in chemical engineering. “It’s a vehicle for the nanoparticles.”

The iron-filled droplet is placed in a playing ‘field’ measuring 2 x 3 millimetres. The team uses four magnets mounted each side of the rectangular field to move the droplet in a figure-8, manoeuvring it through four gates built into the field.

“We use the magnets to pull the droplet,” explains electrical engineering PhD student Remko van den Hurk.

In a second challenge, the team will be required to use the droplet as a bulldozer of sorts, to arrange micro-scale objects that measure 200 x 300 micrometres into a particular order on an even smaller playing field.

The competition has its serious side, these nanobots could one day be used in medical applications.

In the meantime there’s the competition, good luck!