Could Graphene Become the Next Silicon?

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    Graphene Silicon
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Graphene exhibits unique electrical properties, including high conductivity and emerging semiconductive characteristics at narrow dimensions, which could potentially extend Moore's Law. Research indicates that graphene nano-ribbons can create bandgaps, enabling applications in advanced electronics and possibly leading to the development of high-speed circuits. Despite its advantages, graphene devices currently underperform compared to silicon, indicating a need for further optimization. New production methods are being developed to create larger graphene wafers, which could facilitate its use in microprocessors and solar panels. The ongoing exploration of graphene's capabilities suggests it may revolutionize various technologies in the near future.
  • #61
This sounds great, Hans - but as always, what is the quality like?

Here's another story about commercial production of graphene for conductive inks:

http://www.technologyreview.com/business/23129/
 
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  • #62
sanman, while I can't be too specific, the quality is very impressive as far as graphene goes from what I have seen - apparently much less corrugated and discontinuous than graphene made using the scotch tape method. To call it a "new form of carbon" is probably spin put on it by the journalist, as that particular group has been working on that material for a couple years now. It is extremely curious how they managed to create a material that decouples the layers into individual sheets though; some of the more recent literature shows all sorts of weird effects as a result of the misalignment in the layers.

Interesting link though: I have always thought myself that graphene is currently best suited for composite materials. Making all-graphene things is so much harder.
 
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  • #63
I think they're claiming that the specific difference in the chiral angle/orientation between the sheets is what causes the decoupling. How they've achieved that specific difference though, is what's interesting.

Let's see how quickly they can make transistors out of it.
 
  • #64
As it turns out when I was looking at the arXiv paper linked in that phyiscsworld article, it appears that this very recent paper http://arxiv.org/ftp/arxiv/papers/0908/0908.0017.pdf has an author in common. In it they talk about transistors made out of multilayer epitaxial graphene, which is (apparently) the term they use to describe graphene grown on the "C-face" silicon carbide. The on/off ratios are quite modest, which they blame on some substrate problems, so as always there's a catch :smile:
 
  • #65
http://graphenetimes.com/2009/07/epi-sic-first-direct-observation-of-a-nearly-ideal-graphene-band-structure/

EPI SiC ** First direct observation of a nearly ideal graphene band structure

Authors: M. Sprinkle, D. Siegel, Y. Hu, J. Hicks, P. Soukiassian, A. Tejeda, A. Taleb-Ibrahimi, P. Le Fèvre, F. Bertran, C. Berger, W.A. de Heer, A. Lanzara, E.H. Conrad

Angle-resolved photoemission and X-ray diffraction experiments show that multilayer epitaxial graphene grown on the SiC(000-1) surface is a new form of carbon that is composed of effectively isolated graphene sheets. The unique rotational stacking of these films cause adjacent graphene layers to electronically decouple leading to a set of nearly independent linearly dispersing bands (Dirac cones) at the graphene K-point. Each cone corresponds to an individual macro-scale graphene sheet in a multilayer stack where AB-stacked sheets can be considered as low density faults.
 
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  • #66
FirstYearGrad said:
As it turns out when I was looking at the arXiv paper linked in that phyiscsworld article, it appears that this very recent paper http://arxiv.org/ftp/arxiv/papers/0908/0908.0017.pdf has an author in common. In it they talk about transistors made out of multilayer epitaxial graphene, which is (apparently) the term they use to describe graphene grown on the "C-face" silicon carbide. The on/off ratios are quite modest, which they blame on some substrate problems, so as always there's a catch :smile:

The defining trait of a transistor (or a SWITCH for that matter) is the ON/OFF ratio, i.e, non-linearity in circuit characteristics.

In the upper level of hierarchy, the circuit designer does not care at all whether you make your SWITCH out of carbon, silicon, or spin, etc...

Graphene is a zero band-gap semiconductor, it's almost as if it's a short circuit... So currently, there's NO WAY you can fabricate a functional transistor out of graphene UNLESS you find a very good way to induce a band-gap to improve the ON/OFF ratio.

I don't find it surprising that ON/OFF ratios are "quite modest" since this is the single most important problem of graphene. I can't imagine the substrate being the culprit here, because it's a fundamental problem related to the bandstructure of graphene.

It's not another catch, it is THE catch with graphene.
 
  • #68
It still is the mainstream problem... And it will likely be the deal-breaker for graphene.

Of course, striping it and cutting it fine can create a further constriction (ultimately rendering the sheet as 1D rather than 2D) but this is just a fractal solution... Graphene Nanoribbons are likely to be larger in width than tens of nanometers, because you need some decent conductance to utilize it as an electrical switch.

I hear from experimentalists that it could potentially be a valuable interconnect though... Just not a replacement for CMOS...
 
  • #69
Well, interconnects are considered a key bottleneck for increased multiparallelism, in GPUs/vector-processors, for example. So more efficient interconnects from graphene could help address that. As you know, right now GPGPUs (General Purpose Graphics Processing Units) are trying to battle with CPGPUs (Central Processing / Graphics Processing Units) over which becomes the processor of choice for the future. The former are almost purely vector processors with some additional logic to accommodate conventional CPU tasks, while the latter are traditional Central Processing cores with Graphics Processing cores integrated onto the same die. The GPGPU is optimized for throughput by using many parallel cores, while the CPGPU is optimized to reduce latency. Maybe graphene could tip the scales in favor of the GPGPU to become the dominant platform.
 
  • #70
"Camera flash turns an insulating material into a conductor"

http://www.printedelectronicsworld....ial_into_a_conductor_00001684.asp?sessionid=1

Printed Electronics said:
Using patterns printed on a simple overhead transparency film as a photo-mask, flash reduction creates patterned graphene films. This process creates electronically conducting patterns on the insulating graphite oxide film essentially a flexible circuit.


Regards, Hans
 
  • #71
"Graphene mixes it up with GaAs"

http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=220000856

EE Times said:
Pure carbon atoms based on depositing graphene on gallium arsenide wafers could yield the next generation of high performance semiconductors, according to German researchers.


Graphene on Gallium Arsenide: Engineering the visibility. M. Friedemann, K. Pierz, R. Stosch, F. J. Ahlers. Applied Physics Letters, Appl. Phys. Lett. 95, DOI: 10.1063/1.3224910, http://link.aip.org/link/?APL/95/102103


Regards, Hans
 
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  • #73
  • #74
Here's more on that same announcement:

http://www.technologyreview.com/computing/23666/?a=f
 
  • #76
This seems pretty darn interesting:

Observation of the Fractional Quantum Hall Effect in Graphene
http://arxiv.org/abs/0910.2763

When electrons are confined in two dimensions and subjected to strong magnetic fields, the Coulomb interactions between them become dominant and can lead to novel states of matter such as fractional quantum Hall liquids. In these liquids electrons linked to magnetic flux quanta form complex composite quasipartices, which are manifested in the quantization of the Hall conductivity as rational fractions of the conductance quantum. The recent experimental discovery of an anomalous integer quantum Hall effect in graphene has opened up a new avenue in the study of correlated 2D electronic systems, in which the interacting electron wavefunctions are those of massless chiral fermions. However, due to the prevailing disorder, graphene has thus far exhibited only weak signatures of correlated electron phenomena, despite concerted experimental efforts and intense theoretical interest. Here, we report the observation of the fractional quantum Hall effect in ultraclean suspended graphene, supporting the existence of strongly correlated electron states in the presence of a magnetic field. In addition, at low carrier density graphene becomes an insulator with an energy gap tunable by magnetic field. These newly discovered quantum states offer the opportunity to study a new state of matter of strongly correlated Dirac fermions in the presence of large magnetic fields.

Long story short, although the integer quantum Hall effect in graphene has been observed, this is the first observation of the fractional effect. Looks like they found states corresponding to a filling fraction v=0.30, v=0.46 and v=0.68. On theoretical grounds these would probably correspond to v=1/3, v=1/2 and v=2/3 respectively. The v=1/3 and v=2/3 are probably correct, the v=1/2 might be false. T

Some background info: the quantum Hall effect is a topological phase where the bulk of the system develops a mobility gap, thus turning it into an insulator. At the sime time the edges develop massless modes, thus allowing for conductance along the edge. The conductivity is quantized in units of v*e^2/h -- v being an integer or a fractional number. The integer effect is triggered by disorder in the system, the fractional effect requires a dominating Coulomb force.
 
  • #77
IBM demos 100-GHz graphene transistor

EETimes said:
A 100-GHz transistor has been demonstrated by IBM Research. Fabricated on new 2-inch graphene wafers and operating at room temperature, the RF graphene transistors are said to beat the speeds of all but the fastest GaAs transistors, paving the way to commercialization of high-speed, carbon-based electronics
http://www.eetimes.com/news/semi/sh...LHMGL5QE1GHPSKH4ATMY32JVN?articleID=222601227

Very interesting, starting with commercially available SiC wafers!Regards, Hans
 
  • #78
Especially with this new development

Physicists Discover How to Grow Graphene
The discovery of a way to grow graphene should make possible the widespread manufacture of graphene-based electronics.
read it at: http://www.technologyreview.com/blog/arxiv/24746/

Arxiv article: http://arxiv.org/abs/1001.4955

It's basically a new to grow graphene on top of a silicon layer.
 
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  • #79
I haven't read much about graphene in a while and have just started skimming through some of the recent links in this thread, but has there been any significant developments in engineering a band gap in graphene? I know GNRs were showing promise at one point.
 
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  • #80
Carbon semiconductors clear CMOS hurdle
Georgia Tech devises one-step graphene doping

EETimes said:
Carbon semiconductors fashioned from pure crystalline sheets of graphene outperform silicon but have lacked a foolproof method for creating the p- and n-type devices required for complementary metal-oxide semiconductor (CMOS) transistors. Now the Georgia Institute of Technology claims to have a devised a one-step graphene doping process, paving the way for commercial fabrication.

http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=222900570

EETimes said:
The ability to dope with holes (p-type) or with electrons (n-type) from a single dopant material could enable carbon-based CMOS transistors to be fabricated more quickly than silicon transistors. The polymer material, hydrogen silsesquioxane (HSQ), can also be used to increase the conductivity of the graphene ribbons used for interconnections by exposing them to a plasma source.


Regards, Hans
 
  • #81
Hans, you seem to be really well informed. Is there any research using graphene on Racetrack style memories?
 
  • #82
GluonZ said:
I haven't read much about graphene in a while and have just started skimming through some of the recent links in this thread, but has there been any significant developments in engineering a band gap in graphene? I know GNRs were showing promise at one point.
To my knowledge, GNRs are a good way to engineer the band gap. Also, Feng Wang's group in Berkeley demonstrated band gap tuning with a gate field last year[1].

1. Zhang et al, Nature 459, p820 (2009) - http://www.nature.com/nature/journal/v459/n7248/abs/nature08105.html
 
  • #83
Frame Dragger said:
http://www.telecomskorea.com/technology-4195.html Is there any research using graphene on Racetrack style memories?

I haven't seen anything yet. "Racetrack memories" are a sort of revival of the
once very promising "Bubble memories" for instance made by Intel with some
commercial succes.

Well..., even Graphene's magnetic properties can be extra-ordinary it seems...

http://www.telecomskorea.com/technology-4195.html
"In effect, the spin-valve developed by our team permits the graphene nanoribbons to exhibit colossal magnetoresistance properties," the scientist said.

......

The POSTECH professor said tests have shown that the efficiency level of the magnetoresistance of graphene nanoribbons reaches into the million-percent range, compared to few hundred percent for devices created in the past.


Regards, Hans
 
  • #84
Hans de Vries said:
I haven't seen anything yet. "Racetrack memories" are a sort of revival of the
once very promising "Bubble memories" for instance made by Intel with some
commercial succes.

Well..., even Graphene's magnetic properties can be extra-ordinary it seems...

http://www.telecomskorea.com/technology-4195.html



Regards, Hans

I knew you'd come through! Thanks very much Hans, I'll read up on this.
 
  • #85
CMOG(raphene) Devices Near Implementation

http://www.semiconductor.net/article/450922-CMOG_Devices_Near_Implementation.php

www.semiconductor.net said:
A simple one-step process that produces both n- and p-type doping of
large area graphene surfaces may facilitate its use for future electronic
devices. The technique can also increase conductivity in graphene nano-
ribbons used for interconnects.


Regards, Hans
 
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  • #86
Hans de Vries said:
CMOG(raphene) Devices Near Implementation

http://www.semiconductor.net/article/450922-CMOG_Devices_Near_Implementation.php




Regards, Hans


Holy explative deleted. You can't turn your back on computer science for a second. I can't believe they managed to alter the doping just through exposure time, which is an improvement on some vapour deposition methods for non Graphene materials.

It's not often you see a leap towards practicality going hand in hand with success.
 
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  • #87
More good news:

http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/nl904115h
 
  • #88
sanman said:
More good news:

http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/nl904115h

Good time to be alive, when the topic of the thread evolves AHEAD of the discussion! :smile: That is very good news; mass production is a key hurdle for any new material.
 
  • #89
Penn State Synthesizes Graphene Wafer

http://www.semiconductor.net/article/452752-Penn_State_Synthesizes_Graphene_Wafer-full.php
www.semiconductor.net said:
Researchers in the Electro-Optics Center (EOC) Materials Division at Pennsylvania
State University have produced 100 mm diameter graphene wafers, a development
considered to be a critical milestone in the development of graphene for high-
frequency electronic devices

http://www.semiconductor.net/photo/258/258009-A_100_mm_graphene_wafer_with_approximately_75_000_devices_and_test_structures_The_inset_shows_a_single_chip_Source_Penn_State_.jpg

Regards, Hans
 
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  • #90
Hans de Vries said:
Penn State Synthesizes Graphene Wafer

http://www.semiconductor.net/article/452752-Penn_State_Synthesizes_Graphene_Wafer-full.php


http://www.semiconductor.net/photo/258/258009-A_100_mm_graphene_wafer_with_approximately_75_000_devices_and_test_structures_The_inset_shows_a_single_chip_Source_Penn_State_.jpg

Regards, Hans

Explatives Deleted... wow. That's an amazing picture Hans, thanks for sharing.

It looks as though for connections at least, graphene has a mid-near term bright future. Maybe mid-long term as an actual replacement for Si... wow.
 
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