Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Two-Dimensional Layered Materials for High-Performance Electronics

25.05.2012
Graphene is the wonder material that could solve the problem of making ever faster computers and smaller mobile devices when current silicon microchip technology hits an inevitable wall.

Graphene, a single layer of carbon atoms in a tight hexagonal arrangement, is a highly researched material due to its incredible electronic properties, with theoretical speeds 100 times greater than silicon. But putting the material into a microchip that could outperform current silicon technology has proven difficult.

The answer may lie in new nanoscale systems based on ultrathin layers of materials with exotic properties. Called two-dimensional layered materials, these systems could be important for microelectronics, various types of hypersensitive sensors, catalysis, tissue engineering and energy storage. Researchers at Penn State have applied one such 2D layered material, a combination of graphene and hexagonal boron nitride, to produce improved transistor performance at an industrially relevant scale.

“Other groups have shown that graphene on boron nitride can improve performance two to three times, but not in a way that could be scaled up. For the first time, we have been able to take this material and apply it to make transistors at wafer scale,” says Joshua Robinson, assistant professor of materials science and engineering at Penn State and the corresponding author on a paper reporting their work in the online version of the journal ACS Nano.

In the article, the Penn State team describes a method for integrating a thin layer of graphene only one or two atoms thick, with a second layer of hexagonal boron nitride (hBN) with a thickness of a few atoms up to several hundred atoms. The resulting bilayer material constitutes the next step in creating functional graphene field effect transistors for high frequency electronic and optoelectronic devices.

Previous research by other groups has shown that a common material called hexagonal boron nitride (hBN), a synthetic mixture of boron and nitrogen that is used as an industrial lubricant and is found in many cosmetics, is a potential replacement for silicon dioxide and other high-performance dielectrics that have failed to integrate well with graphene. Because boron sits next to carbon on the periodic table, and hexagonal boron nitride has a similar arrangement of atoms as graphene, the two materials match up well electronically. In fact, hBN is often referred to as white graphene. To be of more than academic interest in the lab, however, the hBN-graphene bilayer had to be grown at wafer scale – from around 3 inches (75 mm) to almost 12 inches (300 mm).

The Penn State team solved this problem by using a prior technique developed in their lab to produce a uniform, large-area, and high quality layer of epitaxial graphene suitable for high frequency applications. This “quasi-freestanding epitaxial graphene” was produced by attaching hydrogen atoms to the graphene in order to “passivate dangling bonds,” essentially flattening and smoothing the graphene film. The hexagonal boron nitride was then grown on a transition metal substrate using a chemical vapor deposition technique that is standard in manufacturing. The hBN was released from the substrate via one of several transfer processes and layered on top of the graphene on a 75mm wafer, marking the first integration of epitaxial graphene with hBN on a scale compatible with industry needs.

Building on their earlier work with epitaxial graphene, which had already increased transistor performance by 2-3 times, this research adds a further 2-3x improvement in performance and shows the strong potential for utilizing graphene in electronics, according to Robinson. In the near future, the Penn State team hopes to demonstrate graphene based integrated circuits and high-performance devices suitable for industrial-scale manufacturing on 100mm wafers.

“We use all standard lithography, which is important for nanomanufacturing,” Robinson adds. In order to make a dent in the highly competitive microchip industry, a new material system needs to be compatible with current processing technology as well as offer a significant performance boost.

Boron nitride-graphene is one of several up-and-coming two-dimensional layered systems whose nanoscale properties are only beginning to be discovered. Dimensionality, according to Nobel Laureates Novoselov and Geim, is one of the most defining material parameters and can give rise to dramatically different properties according to whether the material structure is 0D, 1D, 2D, or 3D. Penn State is among the pioneers moving into what may prove to be a new frontier of materials science.

In addition to Robinson, the co-authors on the ACS Nano article are Michael Bresnehan, Matthew Hollander, Maxwell Wetherington, Michael LaBella, Kathleen Trumbull, Randal Cavalero, and David Snyder, all of Penn State. The work was supported by the Naval Surface Warfare Center Crane, and instrumentation support was provided by the National Nanotechnology Infrastructure Network at Penn State. “Integration of Hexagonal Boron Nitride with Quasi-freestanding Epitaxial Graphene: Toward Wafer-Scale High-Performance Devices” was published in online in the April 28, 2012, ASAP (as soon as publishable) edition of ACS Nano. Contact Joshua Robinson at jrobinson@psu.edu.

Joshua Robinson | Newswise Science News
Further information:
http://www.psu.edu

More articles from Materials Sciences:

nachricht Melting solid below the freezing point
23.01.2017 | Carnegie Institution for Science

nachricht An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>