Graphene gets a 'cousin' in the shape of germanene

September 09, 2014

A team of European researchers has become one of the first groups to successfully synthesize the 2D material germanene.

Dubbed a 'cousin of graphene', the material, which is made up of just a single layer of germanium atoms, is expected to exhibit impressive electrical and optical properties and could be widely integrated across the electronics industry in the future.

The material has been presented today, 10 September, in the Institute of Physics and German Physical Society's New Journal of Physics.

Germanene was first proposed in 2009 but has, up until now, remained elusive. Since then, graphene has been developed further whilst other 2D materials, such as silicene, have been synthesized.

Much like silicene, the proposed method for synthesising germanene is to deposit individual germanium atoms onto a substrate under high temperatures and in an ultra-high vacuum.

The breakthrough by the European research team was made in parallel with an independent team from China who have reported evidence that germanene has been synthesized onto a platinum substrate.

In the current study the researchers discovered, rather serendipitously, that gold could also be used as a substrate, an event which co-author of the study Professor Guy Le Lay, from Aix-Marseille University, described as 'like passing through the looking glass'.

'Following our synthesis of graphene's other cousin, silicene, we thought it natural to try and produce germanene in the same way, by despositing germanium onto a silver substrate,' Le Lay said.

'This attempt failed, so I decided to switch to a gold substrate, having remembered my old work from my PhD thesis, in which gold was grown onto a germanium substrate. I thought it would be worth trying the other way around.'

After depositing the germanium atoms onto a gold substrate, the researchers were able to confirm that the material was in fact germanene by taking spectroscopy measurements and density functional theory (DFT) calculations, which investigated the electronic structure of the material.

The material was also observed under a scanning tunnelling microscope, which revealed the characteristic honeycomb structure of a 2D material.

The researchers believe that with further development it may be possible for germanene to be grown on thin gold films sitting on top of a flexible substrate, which would certainly be cheaper than platinum and could allow germanene to be synthesized on a large scale.

Additionally, the unique properties of germanene could make it a robust two-dimensional topological insulator, particularly up to room temperature, opening up the possibility of using the material in quantum computing.

Professor Le Lay continued: 'We have provided compelling evidence of the birth of nearly flat germanene--a novel, synthetic germanium allotrope which does not exist in nature. It is a new cousin of graphene.

'The synthesis of germanene is just the very beginning of a long quest. Indeed, success in the synthesis was not easy to achieve and quite demanding. A considerable amount of work is now needed to further characterize the electronic properties of the material.'

Co-author of the study Professor Angel Rubio, from the University of the Basque Country, added: 'An important aspect of our study is that we have increased the lego of 2D materials that we can use to build a whole host of artificial solid materials with a wide range of differing properties."'
-end-
From Wednesday 10 September, this paper can be downloaded from http://iopscience.iop.org/1367-2630/16/9/095002/article

IOP Publishing

Related Graphene Articles from Brightsurf:

How to stack graphene up to four layers
IBS research team reports a novel method to grow multi-layered, single-crystalline graphene with a selected stacking order in a wafer scale.

Graphene-Adsorbate van der Waals bonding memory inspires 'smart' graphene sensors
Electric field modulation of the graphene-adsorbate interaction induces unique van der Waals (vdW) bonding which were previously assumed to be randomized by thermal energy after the electric field is turned off.

Graphene: It is all about the toppings
The way graphene interacts with other materials depends on how these materials are brought into contact with the graphene.

Discovery of graphene switch
Researchers at Japan Advanced Institute of Science and Technology (JAIST) successfully developed the special in-situ transmission electron microscope technique to measure the current-voltage curve of graphene nanoribbon (GNR) with observing the edge structure and found that the electrical conductance of narrow GNRs with a zigzag edge structure abruptly increased above the critical bias voltage, indicating that which they are expected to be applied to switching devices, which are the smallest in the world.

New 'brick' for nanotechnology: Graphene Nanomesh
Researchers at Japan advanced institute of science and technology (JAIST) successfully fabricated suspended graphene nanomesh (GNM) by using the focused helium ion beam technology.

Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.

Graphene Flagship publishes handbook of graphene manufacturing
The EU-funded research project Graphene Flagship has published a comprehensive guide explaining how to produce and process graphene and related materials (GRMs).

How to induce magnetism in graphene
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechani-cal, electronic and optical properties.

Graphene: The more you bend it, the softer it gets
New research by engineers at the University of Illinois combines atomic-scale experimentation with computer modeling to determine how much energy it takes to bend multilayer graphene -- a question that has eluded scientists since graphene was first isolated.

How do you know it's perfect graphene?
Scientists at the US Department of Energy's Ames Laboratory have discovered an indicator that reliably demonstrates a sample's high quality, and it was one that was hiding in plain sight for decades.

Read More: Graphene News and Graphene Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.