Arindam Ghosh, physicist at the Indian Institute of Science, Bengaluru, talks to Tiasa Adhya about his discovery of a light-sensitive composite material that can revolutionise the way we take pictures, store data and use energy
Could you describe the composite material that your lab has created?
The composite material has individual components which have been miniaturised down to the thinnest possible dimensions—less than two nanometre (nm) thick. In comparison, a sheet of paper is about 100,000 nm thick. We have created a composite of two parallel plates: first, a one atomic layer of graphene (a sheet of carbon atoms arranged in hexagonal manner) and second, one (or few) molecular layers of molybdenum disulphide. Each component of the material works in tandem: The molybdenum disulphide captures light, creates electrons, and transfers them to graphene. Graphene detects the electrons, and from that, one can measure the light.
How is it different from the currently used material?
The light sensing technology usually used in cameras, phones or memory cards have bulk crystals of silicon. Compared to silicon, graphene carries charge much faster, is smaller and has greater sensitivity to light.
It has been said that the composite material is the most sensitive light detector ever. How can it be used?
Compared to silicon, this composite material can detect light which is one billion times lower in intensity. Hence, if the technology is developed appropriately, one can do photography in extremely dim conditions. Although, in the present form, these devices cannot harvest energy, composites of this genre can be used in converting solar light to electric current in the future. I believe these could be used in sectors like defence and security, where non-invasive optical communication is required. Space research is definitely a possibility. The fact that it can detect visible radiation of extremely low intensity should make it promising in detecting far away galaxies.
Are there other labs working on the same subject? How will you take your research forward?
There are several labs developing ultra-thin composite including, IBM, American universities Massachusetts Institute of Technology and Columbia University. We have an advantage because we started before the others and have a great team. We now need to produce the composite on a larger scale and devices that work well in the ambient conditions. The required infrastructure is available with our collaborators at the Center for NanoScience and Engineering in the Indian Institute of Science.
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