Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NRL develops laser processing method to increase efficiency of optoelectronic devices

16.04.2019

Scientists at the U.S. Naval Research Laboratory (NRL) discovered a new method to passivate defects in next generation optical materials to improve optical quality and enable the miniaturization of light emitting diodes and other optical elements.

"From a chemistry standpoint, we have discovered a new photocatalytic reaction using laser light and water molecules, which is new and exciting," said Saujan Sivaram, Ph.D., lead author of the study. "From a general perspective, this work enables the integration of high quality, optically active, atomically thin material in a variety of applications, such as electronics, electro-catalysts, memory, and quantum computing applications."


(Top) Illustration of a water molecule bonding at a sulfur vacancy in the MoS2 upon laser light exposure. (Bottom) Photoluminescence (PL) increase observed during laser light exposure in ambient. (Inset) Fluorescence image showing brightened regions spelling out 'NRL.'

Credit: U.S. Naval Research Laboratory

The NRL scientists developed a versatile laser processing technique to significantly improve the optical properties of monolayer molybdenum disulphide (MoS2) -- a direct gap semiconductor -- with high spatial resolution.

Their process produces a 100-fold increase in the material's optical emission efficiency in the areas "written" with the laser beam.

According to Sivaram, atomically thin layers of transition metal dichalcogenides (TMDs), such as MoS2, are promising components for flexible devices, solar cells, and optoelectronic sensors due to their high optical absorption and direct band gap.

"These semiconducting materials are particularly advantageous in applications where weight and flexibility are a premium," he said. "Unfortunately, their optical properties are often highly variable and non-uniform making it critical to improve and control the optical properties of these TMD materials to realize reliable high efficiency devices."

"Defects are often detrimental to the ability of these monolayer semiconductors to emit light," Sivaram said. "These defects act as non-radiative trap states, producing heat instead of light, therefore, removing or passivating these defects is an important step towards high efficiency optoelectronic devices."

In a traditional LED, approximately 90 percent of the device is a heat sink to improve cooling. Reduced defects enable smaller devices to consume less power, which results in a longer operational lifetime for distributed sensors and low-power electronics.

The researchers demonstrated that water molecules passivate the MoS2 only when exposed to laser light with an energy above the band gap of the TMD. The result is an increase in photoluminescence with no spectral shift.

Treated regions maintain a strong light emission compared to the untreated regions that exhibit much a weaker emission. This suggest that the laser light drives a chemical reaction between the ambient gas molecules and the MoS2.

"This is a remarkable achievement," said Berend Jonker, Ph.D., senior scientist and principal investigator. "The results of this study pave the way for the use of TMD materials critical to the success of optoelectronic devices and relevant to the Department of Defense mission."

###

The research team includes Saujan Sivaram, Ph.D.; Aubrey Hanbicki, Ph.D.; Matthew Rosenberger, Ph.D.; Hsun-Jen Chuang, Ph.D.; Kathleen McCreary, Ph.D.; and Berend Jonker, Ph.D., from the NRL Materials Science and Technology Division, and Glenn Jernigan, Ph.D., from the NRL Electronics Science and Technology Division. Sivaram and Rosenberger hold National Research Council (NRC) fellowships at NRL. Chuang holds an American Society for Engineering Education (ASEE) fellowship at NRL. The research results are reported in ACS Applied Materials & Interfaces; DOI: 10.1021/acsami.9b00390.

Media Contact

Daniel Parry
daniel.parry@nrl.navy.mil
202-767-2326

 @USNRL

http://www.nrl.navy.mil 

Daniel Parry | EurekAlert!
Further information:
https://www.nrl.navy.mil/news/releases/nrl-develops-laser-processing-method-increase-efficiency-optoelectronic-devices
http://dx.doi.org/10.1021/acsami.9b00390

More articles from Process Engineering:

nachricht Roll-to-roll processes: Network R2RNet bundles expertise for the continuous functionalization of surfaces
10.06.2020 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

nachricht Mass production of individualized products
02.06.2020 | Fraunhofer Institute for Electronic Nano Systems ENAS

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Shock-dissipating fractal cubes could forge high-tech armor

08.07.2020 | Materials Sciences

Scientists use nanoparticle-delivered gene therapy to inhibit blinding eye disease in rodents

08.07.2020 | Health and Medicine

'Growing' active sites on quantum dots for robust H2 photogeneration

08.07.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>