SCIENTISTS at the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have created a two-dimensional excitonic laser.
The scientists embedded a monolayer of tungsten disulfide into a special microdisk resonator, achieving bright excitonic lasing at visible light wavelengths.
According to the scientists, the creation of a laser from a single molecular layer of tungsten disulfide marks a major step towards two-dimensional on-chip optoelectronics for high-performance optical communication and computing applications.
This is especially true because a single layer of tungsten and sulphide is widely regarded as one of the most promising 2D semiconductors for photonic and optoelectronic applications.
Two-dimensional transition metal dichalcogenides (TMDCs) are one of the most talked about types of materials for nanotechnology. These 2D semiconductors are said to offer superior energy efficiency, conducting electrons much faster than silicon.
Unlike graphene, another 2D semiconductor class, TMDCs have natural bandgaps that allow their electrical conductance to be switched “on and off,” making them more device-ready than graphene.
While single layer tungsten disulfide has been widely regarded as one of the most promising TMDCs for photonic and optoelectronic applications, this is the first time coherent light emission (lasing) has been possible with the material. Lasing is considered essential for on-chip applications.
The results are described in a paper titled “Monolayer excitonic laser”, published in the journal Nature Photonics.

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