New material, 1000x more sensitive than silicon

Discussion in 'Digital Cameras' started by Alfred Molon, Jun 3, 2013.

  1. Alfred Molon

    Alfred Molon Guest

    http://media.ntu.edu.sg/NewsReleases/Pages/newsdetail.aspx?news=
    863947f9-972d-42d2-947f-3f437f6c3877

    "... The new sensor made from graphene, is believed to be the first to
    be able to detect broad spectrum light, from the visible to mid-
    infrared, with high photoresponse or sensitivity. This means it is
    suitable for use in all types of cameras, including infrared cameras,
    traffic speed cameras, satellite imaging and more.

    Not only is the graphene sensor 1,000 times more sensitive to light than
    current low-cost imaging sensors found in today?s compact cameras, it
    also uses 10 times less energy as it operates at lower voltages. ..."

    This could push the high ISO levels to 1 million - 10 million.
     
    Alfred Molon, Jun 3, 2013
    #1
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  2. Alfred Molon

    Guest Guest

    no it won't. that's not possible. don't fall for the hype and sloppy
    reporting.

    <http://www.dpreview.com/forums/thread/3496509>
    Follow the links that the your links link to. It all comes back to
    this "new" graphene sensor being 10-20 times more sensitive than
    existing graphene sensors, which had yet to exceed an ISO of 1 at the
    time Qijie made his press release.
     
    Guest, Jun 3, 2013
    #2
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  3. Alfred Molon

    RichA Guest

    T.F.B.S.
     
    RichA, Jun 4, 2013
    #3
  4. Alfred Molon

    DanP Guest

    I read about this on a geek site.

    One of the geeks said:
    "They claim 1000 times better sensitivity than CMOS, which people seem to be swallowing hook line
    and sinker, however since there are plenty of current CMOS sensors with a Quantum Sensitiviy (QE)
    of 60% to 80% for visible light, how exactly will the convert 1000 times more efficiently than that?
    1000 times less loss would take them from 80% to 99.99%, that thats only actually 20% better...

    I would imagine they are measuring at an extreme wavelength that existing CMOS sensors do not target,
    hardly an advantage for the applications being discussed in the article (normal cameras).

    Even quite boring consumer cameras have a QE of 20% to 40%.."

    Source is here http://goo.gl/wnDfh


    DanP
     
    DanP, Jun 4, 2013
    #4
  5. Alfred Molon

    Alfred Molon Guest

    I know about these QE values. BTW, the boring consumer cameras (and
    DSLRs as well) are below 30% QE. The 60-80% QE values are for back-
    illuminated sensors.

    I'm not an expert and assuming that the scientists in Singapore are not
    lying, a possible explanation could be standard silicon sensors even if
    they capture a photon and generate an electron somehow lose this
    electron, while the graphene sensors do not. Just guessing however.
     
    Alfred Molon, Jun 4, 2013
    #5
  6. Visible light is a tiny sliver of the spectrum that behaves like light
    so they're probably making claims based on bandwidth. Monocrystaline
    solar cells sometimes produce significant amounts of power in what
    appears to be near darkness because they're using IR light that
    penetrates thick clouds and radiates intensely from dimmed incandescent
    bulbs.
     
    Kevin McMurtrie, Jun 5, 2013
    #6
  7. Alfred Molon

    Mark F Guest

    At this page:
    http://www.gizmag.com/graphene-imaging-sensor/27718/#comments
    Michael Pavel says on 2013 June 2 05:08 PM PDT
    that this page:
    http://www.nature.com/ncomms/journal/v4/n5/full/ncomms2830.html
    says the factor of 1000 is compared to previous graphene-based
    detectors.
    In other words, not compared to CCD or CMOS.

    This is what the www.nature.com abstract says, in part
    (*I had to edit to get rid of special characters in the two
    equations*):
    "Graphene has attracted large interest in photonic applications owing
    to its promising optical properties, especially its ability to
    absorb light over a broad wavelength range, which has lead to several
    studies on pure monolayer graphene-based photodetectorsHowever, the
    maximum responsivity of these photodetectors is below
    10mA/W,
    which significantly limits their potential for applications. Here we
    report high photoresponsivity (with high photoconductive gain) of
    8.61A/W
    in pure monolayer graphene photodetectors, about three orders of
    magnitude higher than those reported in the literature, by
    introducing electron trapping centres and by creating a bandgap in
    graphene through band structure engineering

    NOTE: I am just quoting the abstract. I assume that the units are
    Amperes/Watt
    as per en.wikipedia.org/wiki/Responsivity
    but I'm not sure.
    As above, evidentially an incorrect quote
     
    Mark F, Jun 6, 2013
    #7
  8. http://www.clarkvision.com/articles/digital.sensor.performance.summary/
    Canon 1DMII QE: 38%
    Canon 10D QE: 26%
    Details:
    http://www.clarkvision.com/articles/digital.photons.and.qe/

    So DSLRs can be well above 30% QE (green) on the sensor side.
    Can't be.

    -Wolfgang
     
    Wolfgang Weisselberg, Jun 9, 2013
    #8
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