Energy efficient LEDs and lasers with Chalcogenide monolayers
2 (orange) on top of MoS2 (blue). The SPEEM-microscopy reveals coupling between both layers and charge transfer. © F. Kronast/HZB
As reported by nanotechweb.org, monolayers of certain chalcogenides might be used to make energy-efficient nano-optoelectronics devices, such as LEDs, lasers, solar cells, and high-electron-mobility transistors. Scientists of the University of California at Berkeley, the Lawrence Berkeley National Lab and the Helmholtz-Zentrum Berlin für Materialien und Energie in Berlin investigated the electronic and optoelectronic properties of a so called heterojunction of WSe2/MoS2.
“At BESSY II we performed local x-ray photoemission spectroscopy at the SPEEM microscope and could observe interlayer coupling and charge transfer in this new type of heterojunction”, Dr. Florian Kronast, HZB, explains. This makes these types of heterojunctions interesting candidates for new devices.
To the article in nanotechweb
The present work is detailed in PNAS doi: 10.1073/pnas.1405435111.
- A simpler way to inorganic perovskite solar cellsInorganic perovskite solar cells made of CsPbI3 are stable over the long term and achieve good efficiencies. A team led by Prof. Antonio Abate has now analysed surfaces and interfaces of CsPbI3 films, produced under different conditions, at BESSY II. The results show that annealing in ambient air does not have an adverse effect on the optoelectronic properties of the semiconductor film, but actually results in fewer defects. This could further simplify the mass production of inorganic perovskite solar cells.
- Spintronics: A new path to room temperature swirling spin texturesA team at HZB has investigated a new, simple method at BESSY II that can be used to create stable radial magnetic vortices in magnetic thin films.
- BESSY II: How pulsed charging enhances the service time of batteriesAn improved charging protocol might help lithium-ion batteries to last much longer. Charging with a high-frequency pulsed current reduces ageing effects, an international team demonstrated. The study was led by Philipp Adelhelm (HZB and Humboldt University) in collaboration with teams from the Technical University of Berlin and Aalborg University in Denmark. Experiments at the X-ray source BESSY II were particularly revealing.