Monday, December 22, 2014

Rice University Develops Atomic-Thin CCD

Rice University: Sidong Lei, a graduate student in the Rice lab of materials scientist Pulickel Ajayan, synthesized a single-layer matrix of copper, indium and selenium atoms (CIS). Lei also built a prototype three-pixel CCD to prove the material’s ability to capture an image:


The device traps electrons formed when light hits the material and holds them until released for storage, Lei said. CIS pixels are highly sensitive to light because the trapped electrons dissipate so slowly, said Robert Vajtai, a senior faculty fellow in Rice’s Department of Materials Science and NanoEngineering. “There are many two-dimensional materials that can sense light, but none are as efficient as this material,” he said. “This material is 10 times more efficient than the best we’ve seen before.

No info on the new sensor's QE is given, however article states that the sensor is transparent.

Manufacturing process starts with few-layer exfoliated CIS on a silicon substrate, ten fabricates three pairs of titanium/gold electrodes on top of the CIS and then cuts the CIS into three sections with a focused ion beam.

2 comments:

  1. Idea came from ternary compound semiconductor CuInSe2, which has optical absorption higher than in silicon by the factor of 10+. "single-layer matrix" may be simply a thin layer of CIS semiconductor today widely employed in flexible solar batteries.
    GM

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  2. The original publication is here: http://pubs.acs.org/doi/pdfplus/10.1021/nl503505f

    I would have to say the paper is pretty poor, at least when it comes to the optoelectronic part. In fact, it is not even clear the device operated as a CCD at all - more like an addressable trapped-charge memory device (still interesting).

    These new(ish) materials, esp. when published by people in chemistry or materials science, are usually very poor in performance compared to silicon but the authors don't have enough experience in our field to understand how far away they are from a useful material.

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