Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Lighting the way to miniature devices


Electromagnetic waves created on a layer of organic molecules could provide the perfect on-chip light source for future quantum communication systems.

A team of scientists including A*STAR researchers has captured tiny flashes of light from an ultrathin layer of organic molecules sandwiched between two electrodes that could replace lasers and LEDs as signal sources for future miniature, ultrafast quantum computing and light-based communication systems1.

Electron tunneling (pink) through a single organic molecule gives rise to plasmons (blue ripples) at the interface between the organic layer and the electrode below.

© 2016 Tao Wang, NUS.

To investigate electromagnetic waves called plasmons, which skim along the interface between two materials, Nikodem Tomczak from the A*STAR Institute of Materials Research and Engineering and colleagues collaborated with Christian A. Nijhuis from the National University of Singapore to construct a junction consisting of a layer of thiol molecules on a metal electrode and liquid gallium-indium alloy as a top electrode.

The team created plasmons by applying a voltage across the thiol layer. Although thiol is an insulator, the layer was thin enough for electrons to quantum tunnel between the electrodes, exciting plasmons on the thiol layer’s surface in the process. The plasmons then decayed into photons, tiny pulses of light that Tomczak and his colleagues were able to detect.

“We were surprised that the light did not come from the whole junction, but instead just from very small spots that blink at different frequencies,” said Tomczak.

The team found that the light generated by the plasmons was polarized, and that both the polarization and the wavelength of the light varied with the voltage applied across the junction and the molecules used to form the organic layer.

“The spots are diffraction-limited, polarized and their blinking follows power-law statistics,” said Tomczak. “We need further experiments to confirm, but it is very similar to emission from other single photon sources, such as quantum dots or nanodiamonds.”

Further evidence that the light is from plasmons decaying into a single photon came from Chu Hong Son and his team at the A*STAR Institute of High Performance Computing who modeled the spots as the product of the smallest possible source, a single dipole emitter, and achieved results consistent with the experimental observations.

Tomczak believes the layers can be scaled down to junctions built from a single molecule, opening up the potential to integrate plasmonic light sources on to silicon-based circuits, replacing large external light sources such as a laser.

The team also explored one-molecule thick layers of carbon chains terminated with a metallic ferrocene group developed by the group of Christian A. Nijhuis. Because this compound is asymmetric, it allows tunneling in one direction, effectively acting as a diode.

“By keeping the same architecture and tuning the chemistry of the monolayer you can create a range of different devices,” said Tomczak.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering and the Institute of High Performance Computing.


  1. Du, W., Wang, T., Chu, H.-S., Wu, L., Liu, R. et al. On-chip molecular electronic plasmon sources based on self-assembled monolayer tunnel junctions. Nature Photonics 10, 274–280 (2016). | Article

A*STAR Research | Research SEA
Further information:

More articles from Physics and Astronomy:

nachricht Physicists made crystal lattice from polaritons
20.03.2018 | ITMO University

nachricht Mars' oceans formed early, possibly aided by massive volcanic eruptions
20.03.2018 | University of California - Berkeley

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Physicists made crystal lattice from polaritons

20.03.2018 | Physics and Astronomy

Mars' oceans formed early, possibly aided by massive volcanic eruptions

20.03.2018 | Physics and Astronomy

Thawing permafrost produces more methane than expected

20.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>