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Science Forum

  1. 05 Jul '12 10:36 / 4 edits
    Graphene is said to be the most conductive material in the universe ( at room temperature I assume else a superconductor would be more conductive ) and has several properties that make it suitable for nano electronics especially in microchips. But much emphasis is placed on the fact that it doesn't have a band-gap and that makes it hard to use it as a semiconductor in a transistor.

    But I really fail to see why such emphasis is placed on this fact because I fail to see why this is a problem because, and this is my burning question here, why not just use the graphene for wherever you need conductors in a microchip ( which will be in the transistor leads and nano-wires ) but simply use a none-graphene semiconductor ( perhaps doped silicene? ) wherever you need a semiconductor ( which will be in the transistors where the leads meet ) ? I mean, is there something I am missing here? I mean, is there a reason I am not aware of why doing that would be problematic?


    Also, graphene is made of pure carbon and silicene is like graphene in structure but made of pure silicon. But what is the graphene analogy for carborundum ( Silicon carbide ( SiC ) ) ? You could have a 2D graphene structure but where each atom of carbon is bonded to 3 silicon atoms and each silicon atom is bonded to 3 carbon atoms. What would such a material be called? ( I tried googling various wildly guessed names such as “carborundumene” and “siligraphene” but had no luck ) and what would be its electrical properties ( if known ) and has this material been researched as a possible material for electronics? ( any web links? )
  2. 05 Jul '12 11:50
    http://en.wikipedia.org/wiki/Ballistic_transistor
  3. 05 Jul '12 13:12 / 1 edit
    Originally posted by googlefudge
    http://en.wikipedia.org/wiki/Ballistic_transistor
    That is interesting although not sure what this has got to do with my questions.

    I found this on ballistic transistors:

    http://www.rochester.edu/news/show.php?id=2585

    “...Some of these groups are working on similar single-electron transistors, but these designs still compute by starting and stopping the flow of electrons just like conventional designs. But the Ballistic Deflection Transistor adds a new twist by bouncing the electrons into their chosen trajectories—using inertia to redirect for "free," instead of wrestling the electrons into place with brute energy.
    Such a chip would use VERY LITTLE POWER, create very little heat, be highly resistant to "noise" inherent in electronic systems, and should be easy to manufacture with current technologies. … (my emphasis) ...”

    -in bold figures, how much less power I wonder?
    But this research appears to be done in ~2006 and I cannot find any links to more recent research on ballistic transistors so perhaps this line of research has reached a dead-end? if so, what went wrong with the idea of ballistic transistors?
  4. Subscriber Ponderableonline
    chemist
    05 Jul '12 13:37
    Originally posted by humy
    That is interesting although not sure what this has got to do with my questions.

    I found this on ballistic transistors:

    http://www.rochester.edu/news/show.php?id=2585

    “...Some of these groups are working on similar single-electron transistors, but these designs still compute by starting and stopping the flow of electrons just like conventional designs. ...[text shortened]... earch has reached a dead-end? if so, what went wrong with the idea of ballistic transistors?
    The short answer on power consumtion is you save about half. (That answer is not true in the struct sense of the word, but the value is very hard to pin down. Point in question is of course that you won't find the excluive electric power use of an transistor)

    There is ongoing research and publications in the scientific lietrature for example:


    Wolpert, D., Iniguez-De-La-Torre, I., Kaushal, V., Margala, M., Ampadu, P.
    Proceedings of the IEEE Conference on Nanotechnology , art. no. 6144451 , pp. 1171-1176
  5. Subscriber Ponderableonline
    chemist
    05 Jul '12 13:42
    Originally posted by humy
    Graphene is said to be the most conductive material in the universe ( at room temperature I assume else a superconductor would be more conductive ) and has several properties that make it suitable for nano electronics especially in microchips. But much emphasis is placed on the fact that it doesn't have a band-gap and that makes it hard to use it as a semicondu ...[text shortened]... nd has this material been researched as a possible material for electronics? ( any web links? )
    I will also have a go at the original question:

    * the contacting of graphene is still a problem, as is the production as conductive layer.

    as for the silicon graphene analogon:

    As opposed to carbon silicon is not able to exist in the "aromatic" configuration, due to geometrical and energetical reasons. So there is no silicon analogon to graphene (knowledge of today).
  6. 05 Jul '12 17:45 / 3 edits
    Originally posted by Ponderable
    I will also have a go at the original question:

    * the contacting of graphene is still a problem, as is the production as conductive layer.

    as for the silicon graphene analogon:

    As opposed to carbon silicon is not able to exist in the "aromatic" configuration, due to geometrical and energetical reasons. So there is no silicon analogon to graphene (knowledge of today).
    * the contacting of graphene is still a problem, as is the production as conductive layer.


    is this “contacting” referring to the contacting between some graphene and a semiconductor?

    As opposed to carbon silicon is not able to exist in the "aromatic" configuration, due to geometrical and energetical reasons.


    but surely, ignoring the issue of how to synthesizing it, from my understanding of physical chemistry and covalent bonds, it is possible to have a ring of 6 atoms as a molecule's backbone with carbon-silicon-carbon-silicon-carbon-silicon order? It can be just like a benzene molecule but with 3 of the carbon atoms replaced with silicon atoms.
    This isn't exactly the same thing but look at “silacyclopentadienes” at http://en.wikipedia.org/wiki/Organosilicon which are ring shaped molecules that have 4 carbon atoms and one silicon atom as their backbone -that isn't quite what I am looking for but is getting close to what I mean.
  7. 05 Jul '12 21:53
    Originally posted by Ponderable
    I will also have a go at the original question:

    * the contacting of graphene is still a problem, as is the production as conductive layer.

    as for the silicon graphene analogon:

    As opposed to carbon silicon is not able to exist in the "aromatic" configuration, due to geometrical and energetical reasons. So there is no silicon analogon to graphene (knowledge of today).
    Boron nitride can however...