From graphene to graphane, now the possibilities are endless

July 31, 2009
Physics World

Ever since graphene was discovered in 2004, this one-atom thick, super strong, carbon-based electrical conductor has been billed as a "wonder material" that some physicists think could one day replace silicon in computer chips.

But graphene, which consists of carbon atoms arranged in a honeycomb lattice, has a major drawback when it comes to applications in electronics - it conducts electricity almost too well, making it hard to create graphene-based transistors that are suitable for .

In August's Physics World, Kostya Novoselov - a condensed-matter physicist from the Manchester University group that discovered graphene -- explains how their discovery of graphane, an insulating equivalent of graphene, may prove more versatile still.

Graphane has the same honeycomb structure as graphene, except that it is "spray-painted" with that attach themselves to the carbon. The resulting bonds between the and carbon atoms effectively tie down the electrons that make graphene so conducting. Yet graphane retains the thinness, super-strength, flexibility and density of its older chemical cousin.

One advantage of graphane is that it could actually become easier to make the tiny strips of graphene needed for electronic circuits. Such structures are currently made rather crudely by taking a sheet of the material and effectively burning away everything except the bit you need. But now such strips could be made by simply coating the whole of a graphene sheet - except for the strip itself - with hydrogen. The narrow bit left free of hydrogen is your conducting graphene strip, surrounded by a much bigger graphane area that electrons cannot go down.

As if this is not enough, the physicists in Manchester have found that by gradually binding hydrogen to graphene they are able to drive the process of transforming a conducting material into an insulating one and watch what happens in between.

Perhaps most importantly of all, the discovery of graphane opens the flood gates to further chemical modifications of graphene. With metallic graphene at one end and insulating graphane at the other, can we fill in the divide between them with, say, graphene-based semiconductors or by, say, substituting hydrogen for fluorine?

As Professor Novoselov writes, "Being able to control the resistivity, optical transmittance and a material's work function would all be important for photonic devices like solar cells and liquid-crystal displays, for example, and altering mechanical properties and surface potential is at the heart of designing composite materials. Chemical modification of - with graphane as its first example - uncovers a whole new dimension of research. The capabilities are practically endless."

Source: Institute of Physics (news : web)

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earls
not rated yet Jul 31, 2009
Graphene is awesome, and this research is no exception.

I'm definitely more interested in the possibilities of superconducting graphene. Such can be accomplished by doping the graphene with Calcium. I believe this gives us our best chance yet to observe the superconduction mechanism and unlock RTSC.
Velanarris
4.3 / 5 (3) Jul 31, 2009
I'd say we're exiting the silicon age and entering the carbon age.
antialias
not rated yet Jul 31, 2009
This looks very compatible with curent fabrication methods for doping silicon (which is important because companies don't like to invest in new/unproven technology). Now if someone can just come up with a procedure for manufacturing large/high quality graphen sheets things will take off pretty quickly.
otto1923
not rated yet Jul 31, 2009
Any closer to thermoelectrics? Any way of producing current from heat with a composite material which could be laminated into car finishes, roofing material, parking lot pavement, roads, etc, as sheets or tape grids?
earls
not rated yet Jul 31, 2009
Does carbon/graphene have thermoelectric properties? I can see why it might, but have heard nothing on the research front.
pseudophonist
not rated yet Aug 01, 2009
The biggest advantages silicon has currently is that

1) It can be carted around the lab in large wafers and handled easily

2) It can be doped p or n type (though this is less important if another kind(not BJT or MOSFET) of transistor can be made with graphene/graphane)

3) It's cheap to produce and purify to a high quality.

4) Multistorey circuits are possible.



Solve these problems and we'll have a true carbon age. What's great is that these don't seem insurmountable. Silicon's biggest plus is that Silicon dioxide is a great isulator; and now graphane does the same for graphene!



Exciting stuff!

probes
not rated yet Aug 03, 2009
this is fantastic news. even better than q-bit computers. really great.
El_Nose
5 / 5 (3) Aug 03, 2009
The only reason silicon has any advantage is the millions of man-hours and money already in it -- we know everything there is to know about silicon... it will take just as many man-hours and just as much money to overtake silicon but once it starts it will be like trains overtaking canals -- or cars overtaking horses ... all improvements in technology are like that... make it stylish make it cheap ... make people think they thought of it first
earls
not rated yet Aug 03, 2009
"Recent experiments have shown the absence of the thermoelectric effect in metallic carbon nanotubes."

Whoops.
houseofcards
not rated yet Aug 05, 2009
What about ultracapacitors made by sandwiching graphene and graphane? Interesting/Doable?

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