Study opens graphene band-gap

Dec 18, 2013
This is a schematic representation for the formation of BCN-graphene via solvothermal reaction between carbon tetrachloride (CCl4) boron tribromide (BBr3) and nitrogen (N2) in the presence of potassium (K). Photograph is of the autoclave after the reaction, showing the formation of BCN-graphene (black) and potassium halide (KCl and KBr, white). Credit: UNIST

Ulsan National Institute of Science and Technology (UNIST) announced a method for the mass production of boron/nitrogen co-doped graphene nanoplatelets, which led to the fabrication of a graphene-based field -effect transistor (FET) with semiconducting nature. This opens up opportunities for practical use in electronic devices.

The Ulsan National Institute of Science and Technology (UNIST) research team led by Prof. Jong-Beom Baek have discovered an efficient method for the of /nitrogen co-doped graphene nanoplatelets (BCN-graphene) via a simple solvothermal reaction of BBr3/CCl4/N2 in the presence of potassium. This work was published in Angewandte Chemie International Edition as a "Very Important Paper".

Since graphene was experimentally discovered in 2004, it has been the focus of vigorous applied research due to its outstanding properties such as high specific surface area, good thermal and electrical conductivities, and many more properties.

However, its Achilles heel is a vanishing band-gap for semiconductor application. As a result, it is not suitable for logic applications, because devices cannot be switched off. Therefore, graphene must be modified to produce a band-gap, if it is to be used in .

Various methods of making graphene-based field effect transistors (FETs) have been exploited, including doping graphene, tailoring graphene-like a nanoribbon, and using as a support. Among the methods of controlling the band-gap of graphene, doping methods show the most promisinge in terms of industrial scale feasibility.

This is a schematic representation for the formation of BCN-graphene via solvothermal reaction between carbon tetrachloride (CCl4) boron tribromide (BBr3) and nitrogen (N2) in the presence of potassium (K). Credit: UNIST

Although world leading researchers have tried to add boron into graphitic framework to open its band-gap for semiconductor applications, there has not been any notable success yet. Since the atomic size of boron (85 pm) is larger than that of carbon (77 pm), it is difficult to accommodate boron into the graphitic network structure.

A new synthetic protocol developed by a research team from UNIST, a leading Korean university, has revealed that boron/nitrogen co-doping is only feasible when carbon tetrachloride (CCl4 ) is treated with boron tribromide (BBr3 ) and nitrogen (N2) gas.

In order to help boron-doping into graphene structure, the research team used nitrogen (70 pm), which is a bit smaller than carbon and boron. The idea was very simple, but the result was surprising. Pairing two nitrogen atoms and two can compensate for the atomic size mismatch. Thus, boron and nitrogen pairs can be easily introduced into the graphitic network. The resultant BCN-graphene generates a band-gap for FETs.

"Although the performance of the FET is not in the ranges of commercial silicon-based semiconductors, this initiative work should be the proof of a new concept and a great leap forward for studying with band-gap opening," said Prof. Jong-Beom Baek.

"I believe this work is one of the biggest advancements in considering the viability of a simple synthetic approach," said Ph.D. candidate Sun-Min Jung, the first author of this article.

Prof. Baek explains the next step: "Now, the remaining challenge is fine-tuning a band-gap to improve the on/off current ratio for real device applications."

Explore further: Graphene: Minor rotation of 'chicken wire' has major consequences

add to favorites email to friend print save as pdf

Related Stories

Stacking 2-D materials produces surprising results

May 16, 2013

(Phys.org) —Graphene has dazzled scientists, ever since its discovery more than a decade ago, with its unequalled electronic properties, its strength and its light weight. But one long-sought goal has proved ...

Direct nitrogen fixation for low cost energy conversion

Jul 23, 2013

A simple, low-cost and eco-friendly method of creating nitrogen-doped graphene nanoplatelets (NGnPs), which could be used in dye-sensitized solar cells and fuel cells, is published in Scientific Reports today. ...

Defective nanotubes turned into light emitters

Oct 31, 2013

Scientists are usually after defect-free nano-structures. Yet in this case the UPV/EHU researcher Angel Rubio and his collaborators have put the structural defects in boron nitride nanotubes to maximum use. ...

Recommended for you

Tiny graphene drum could form future quantum memory

Aug 28, 2014

Scientists from TU Delft's Kavli Institute of Nanoscience have demonstrated that they can detect extremely small changes in position and forces on very small drums of graphene. Graphene drums have great potential ...

Graphene reinvents the future

Aug 27, 2014

For many scientists, the discovery of one-atom-thick sheets of graphene is hugely significant, something with the potential to affect just about every aspect of human activity and endeavour.

User comments : 0