Featured Research

from universities, journals, and other organizations

New rapid synthesis developed for bilayer graphene and high-performance transistors

Date:
May 1, 2014
Source:
University of California - Santa Barbara
Summary:
A research team has demonstrated a rapid synthesis technique for large-area Bernal -- or AB -- stacked bilayer graphene films that can open up new pathways for digital electronics and transparent conductor applications.

This is concept art of a schematic view of an AB-stacked graphene film synthesized by UC Santa Barbara researchers using a stoichiometry engineered bifunctional alloy catalyst.
Credit: Peter Allen, UCSB

UC Santa Barbara researchers demonstrate ultra-fast and deterministic growth of high-quality and large-area bilayer graphene films with controlled stacking order required for low-power digital electronics.

Related Articles


Researchers at University of California, Santa Barbara, in collaboration with Rice University, have recently demonstrated a rapid synthesis technique for large-area Bernal (or AB) stacked bilayer graphene films that can open up new pathways for digital electronics and transparent conductor applications.

The invention also includes the first demonstration of a bilayer graphene double-gate field-effect transistor (FET), showing record ON/OFF transistor switching ratio and carrier mobility that could drive future ultra-low power and low-cost electronics.

Graphene is the thinnest known (~0.5 nanometer per layer) 2-dimensional atomic crystal. It has attracted wide interest due to its promising electrical and thermal properties and potential applications in electronics and photonics. However, many of those applications are significantly restricted by the zero band gap of graphene that results in leaky transistors not suitable for digital electronics.

"In addition to its atomically smooth surfaces, a considerable band gap of up to ~0.25 eV can be opened up in bilayer graphene by creating a potential difference between the two layers, and thereby breaking the inherent symmetry, if the two layers can be aligned along a certain (Bernal or AB) orientation" explained Kaustav Banerjee, professor of electrical and computer engineering and Director of the Nanoelectronics Research Lab at UCSB. "The dual-gated transistors were specifically designed to allow such potential difference to be established between the layers through one of the gates, while the second gate modulated the carriers in the channel," he added. Banerjee's research team also includes UCSB researchers Wei Liu, Stephan Kraemer, Deblina Sarkar, Hong Li and Professor Pulickel Ajayan of Rice University. Their study was recently published in Chemistry of Materials.

The graphene films were grown in a deterministic manner using an engineered bifunctional (Cu:Ni) alloy surface at a relatively low temperature of 920 C. Large-area (> 3 inch 3 inch) Bernal (or AB) stacked bilayer graphene growth was demonstrated within few minutes and with nearly 100% area coverage. The bilayer graphene films exhibited electron mobility as high as 3450 cm2/(V•s), which is comparable to that of exfoliated bilayer graphene, thereby confirming very high-quality. The quality of grown graphene was further corroborated by demonstration of high-performance FETs with record ON/OFF ratio that is a key requirement in low-power digital electronics.

"Achieving surface catalytic graphene growth mode and precise control of the surface carbon concentration were key factors for the favorable growth kinetics for AB stacked bilayer graphene," explained Wei Liu, a post-doctoral researcher in Banerjee's group and a co-author of the article. In 2011, Banerjee's group demonstrated a large-area monolayer graphene synthesis method using a copper substrate as catalyst.

Bilayer graphene is close to monolayer graphene in terms of the film thickness with a hexagonal atomic structure and can be derived from its layered bulk form (graphite) in which adjacent layers are held together by relatively weak van der Waals forces. "However, apart from its band gap tunability, bilayer graphene has some key advantages over monolayer graphene. It has higher density of states and suffers much less from interface effects, which are beneficial for improving the current carrying capability," Liu continued.

"This demonstration is very impressive and should have far-reaching implications for the entire 2D materials community," commented Professor Ali Javey, of University of California, Berkeley and a Co-Director of the Bay Area Photovoltaic Consortium (BAPVC).


Story Source:

The above story is based on materials provided by University of California - Santa Barbara. Note: Materials may be edited for content and length.


Journal Reference:

  1. Wei Liu, Stephan Kraemer, Deblina Sarkar, Hong Li, Pulickel M. Ajayan, Kaustav Banerjee. Controllable and Rapid Synthesis of High-Quality and Large-Area Bernal Stacked Bilayer Graphene Using Chemical Vapor Deposition. Chemistry of Materials, 2014; 26 (2): 907 DOI: 10.1021/cm4021854

Cite This Page:

University of California - Santa Barbara. "New rapid synthesis developed for bilayer graphene and high-performance transistors." ScienceDaily. ScienceDaily, 1 May 2014. <www.sciencedaily.com/releases/2014/05/140501101125.htm>.
University of California - Santa Barbara. (2014, May 1). New rapid synthesis developed for bilayer graphene and high-performance transistors. ScienceDaily. Retrieved December 17, 2014 from www.sciencedaily.com/releases/2014/05/140501101125.htm
University of California - Santa Barbara. "New rapid synthesis developed for bilayer graphene and high-performance transistors." ScienceDaily. www.sciencedaily.com/releases/2014/05/140501101125.htm (accessed December 17, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Wednesday, December 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Sony Hopes To Make Any Glasses 'Smart'

How Sony Hopes To Make Any Glasses 'Smart'

Newsy (Dec. 17, 2014) Sony's glasses module attaches to the temples of various eye- and sunglasses to add a display and wireless connectivity. Video provided by Newsy
Powered by NewsLook.com
Los Angeles Police To Receive 7,000 Body Cameras

Los Angeles Police To Receive 7,000 Body Cameras

Newsy (Dec. 17, 2014) Los Angeles Mayor Eric Garcetti announced the cameras will be distributed starting Jan. 1. Video provided by Newsy
Powered by NewsLook.com
Researchers Bring Player Pianos Back to Life

Researchers Bring Player Pianos Back to Life

AP (Dec. 17, 2014) Stanford University wants to unlock the secrets of the player piano. Researchers are restoring and studying self-playing pianos and the music rolls that recorded major composers performing their own work. (Dec. 17) Video provided by AP
Powered by NewsLook.com
France's Sauternes Wine Threatened by New Train Line

France's Sauternes Wine Threatened by New Train Line

AFP (Dec. 16, 2014) Winemakers in southwestern France's Bordeaux are concerned about a proposed high speed train line that could affect the microclimate required for the region's sweet wine. Duration: 01:06 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins