Researchers Yuehang Xu and his team at Columbia University in New York has been able to make a nano scale Radio receiver using Graphene Sheet. They buit nanotrampoline out of graphene that can directly detect radio frequency signals, paving the way for a new generation of radios.
|Graphene Sheet Radio Receiver|
Picture shows how the Graphene Sheet has been placed on top of a FET which induces DC current in Graphene when the Radio waves strike. They say the graphene sheet resonates when blasted with a voltage changing at radio frequency signals and that this can be easily measured by monitoring the capacitance between the sheet and the third electrode below the sheet.
That’s a significant result. For some time now, physicists have been hoping to find ways of using nanoelectromechanical resonators to filter and generate radio signals directly. At present, this has to be done with various kinds of mixing techniques. The problem is that nanoelectromechanical devices all suffer from parasitic capacitance, which tends to drown out the signals that physicists are interested in at radio frequencies.
Graphene sheet device is immune from this because its design causes the effects of stray capacitance essentially to cancel out. And they prove it by using their device to pick out a radio frequency signal at 33.27 MHz.
Graphene sheets are two orders of magnitude less massive than similar devices made of silicon and so can measure signals at much higher frequency. Xu and Team say, they should be able to measure signals in the GHz range. The new device works at 77K so its operating temperature will need to be boosted before it can be used in consumer devices. Neither of those problems seem like showstoppers, however.
Physicists have known about the amazing properties of graphene for a decade or so now. They’ve even predicted that it will take the world of microelectronics by storm. What nobody really appreciated was how quickly this would happen. Now we’re finding out.
Here is the Ref: arXiv:1012.4415