Researchers in electrical and computer engineering at UC Santa Barbara have introduced and modeled an integrated circuit design scheme in which transistors and interconnects are monolithically patterned seamlessly on a sheet of graphene, a 2-dimensional plane of carbon atoms. The demonstration offers possibilities for ultra energy-efficient, flexible, and transparent electronics.
Bulk materials commonly used to make CMOS transitors and interconnects pose fundamental challenges in continuous shrinking of their feature-sizes and suffer from increasing "contact resistance" between them, both of which lead to degrading performance and rising energy consumption. Graphene-based transistors and interconnects are a promising nanoscale technology that could potentially address issues of traditional silicon-based transistors and metal interconnects.
"In addition to its atomically thin and pristine surfaces, graphene has a tunable band gap, which can be adjusted by lithographic sketching of patterns - narrow graphene ribbons can be made semiconducting while wider ribbons are metallic. Hence, contiguous graphene ribbons can be envisioned from the same starting material to design both active and passive devices in a seamless fashion and lower interface/contact resistances," explained Kaustav Banerjee, professor of electrical and computer engineering and director of the Nanoelectronics Research Lab at UCSB. Banerjee's research team also includes UCSB researchers Jiahao Kang, Deblina Sarkar and Yasin Khatami. Their work was recently published in the journal Applied Physics Letters.
"Accurate evaluation of electrical transport through the various graphene nanoribbon based devices and interconnects and across their interfaces was key to our successful circuit design and optimization," explained Jiahao Kang, a PhD student in Banerjee's group and a co-author of the study. Banerjee's group pioneered a methodology using the Non-Equilibrium Green's Function (NEGF) technique to evaluate the performance of such complex circuit schemes involving many heterojunctions. This methodology was used in designing an "all-graphene" logic circuit reported in this study.
"This work has demonstrated a solution for the serious contact resistance problem encounterd in conventional semiconductor technology by providing an innovative idea of using an all-graphene device-interconnect scheme. This will significantly simplify the IC fabrication process of graphene based nanoelectronic devices." commented Philip Kim, professor of physics at Columbia University, and a renowned scientist in the graphene world.
As reported in their study, the proposed all-graphene circuits have achieved 1.7X higher noise margins and 1-2 decades lower static power consumption over current CMOS technology. According to Banerjee, with the ongoing worldwide efforts in patterning and doping of graphene, such circuits can be realized in the near future.
"We hope that this work will encourage and inspire other researchers to explore graphene and beyond-graphene emerging 2-dimensional crystals for designing such ‘band-gap engineered' circuits in the near future," added Banerjee.
Their research was supported by the National Science Foundation.
The College of Engineering at University of California, Santa Barbara is recognized globally as a leader among the top tier of engineering education and research programs, and is renowned for a successful interdisciplinary approach to engineering research.Media Contact
Melissa Van De Werfhorst | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering