An electrical circuit operating at frequencies of hundreds of terahertz has been develop by researchers in Singapore promising tens of thousands times better performance than the best of today’s microprocessors.
The scientific breakthrough achieved by a team at the National University of Singapore promises to revolutionise high-speed electronics, nanoscale opto-electronics and nonlinear optics.
The circuit uses a physical process called quantum plasmonic tunneling. By changing the molecules in the molecular electronic device, the frequency of the circuits can be altered by hundreds of terahertz.
The device, described in the latest issue of the Science journal, could potentially be used to construct ultra-fast computers or single molecule detectors, and open up new possibilities in nano-electronic devices.
“We are very excited by the new findings,” said Assistant Professor Christian A Nijhuis, one of the authors of the study. “Our team is the first to observe the quantum plasmonic tunneling effects directly. This is also the first time that a research team has demonstrated theoretically and experimentally that very fast-switching at optical frequencies is indeed possible in molecular electronic devices.”
The molecular electronic circuit was fabricated using two plasmonic resonators - structures capable to capture light in the form of plasmons - bridged by a layer of molecules that is exactly one molecule thick. The layer of molecules switches on the quantum plasmonic tunneling effect, enabling the circuit to operate at terahertz frequencies.
Scientists have long known that light can interact with certain metals and can be captured in the form of plasmons, which are collective, ultra-fast oscillations of electrons that can be manipulated at the nano-scale.
The so-called quantum plasmon modes have been theoretically predicted to occur at atomic length scales. However, current state-of-the-art fabrication techniques can only reach length scales of about five nanometres large, therefore the quantum-plasmon effect has been difficult to investigate.