A research team developed a 2D laser that can be used to further pave the way of developing a new generation of photonic and optoelectronic devices.
Scientists from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) were able to produce bright excitonic lasers by embedding a monolayer of tungsten into a specially made microdisk resonator.
This high quality lasing marks a major step forward in efforts to develop next generation optoelectronics, according to study lead author Xiang Zhang, director of Berkeley Lab's Materials Sciences Division.
"Our observation...marks a major step towards two-dimensional on-chip optoelectronics for high-performance optical communication and computing applications," Zhang said.
The material involved in the experiment is a form of 2D transition metal dichalcogenides (TMDCs), which are energy efficient and can conduct electrons at a much greater pace compared to silicon. This kind of 2D semiconductor also possesses natural bandgaps, allowing electrical transfer to be switched between active or inactive, unlike the most commonly used graphene.
Zhang added however that the properties of the fashioned monolayer will need a high quality, or Q factor to produce the 2D laser, hence the need for the specially designed microdisk resonator.
The idea behind the resonator was based on the findings of a study also headed by Zhang wherein the team was able to develop a "whispering gallery microcavity." Based on the principle that whispers from opposite ends can be heard clearly in a building with a domed ceiling, the researchers were able to adapt it for electromagnetic waves rolling across metals, or plasmons.
The resonator, designed with this thought in mind, was able to greatly strengthen and enhance the light emissions' Q factor.
"TMDCs have shown exceptionally strong light-matter interactions that result in extraordinary excitonic properties," said Zhang. "These properties arise from the quantum confinement and crystal symmetry effect on the electronic band structure as the material is thinned down to a monolayer."
The findings on TMDCs will prove useful not only in making photonic devices, but also in valleytronic applications, wherein digital information encoding is done through the momentum of an electron in a crystal lattice.
The research was published in the journal Nature Photonics.
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