Project description
Tiny domes with novel optical properties open the door to innovative optoelectronics devices
Transition metal dichalcogenide monolayers are a class of atomically thin 2D nanosheets consisting of a transition metal and a chalcogen. They are of extreme interest for numerous applications because of their unique optoelectronic properties. However, to exploit these materials in commercial applications, we need reproducible and cost-effective manufacturing routes for large-scale production. The EU-funded SELENe project will tackle this important bottleneck by producing single-layer-thick domes from multilayer samples via hydrogen irradiation. These tiny exotic domes will then be characterised for their as yet unknown optical properties and potential application in high-tech optoelectronics structures.
Objective
When transition metal dichalcogenides (TMDs) are thinned down to monolayer thickness, they exhibit a direct bang gap at the K and K’ points of the Brillouin zone, which represents a binary quantum degree of freedom, referred to as valley pseudospin. The fabrication of high quality samples is currently based on the mechanical exfoliation of monolayer flakes from bulk crystal. While this approach gives excellent results at the laboratory scale, it lacks potential for upscaling, in particular if one wants to achieve a systematic coupling with surrounding photonic structures. This drawback can be overcome by controllably creating single-layer thick domes by performing hydrogen irradiation of a multilayer TMD sample. SELENe aims at exploiting this fabrication approach to perform a paradigm-shifting experimental activity, which merges the investigation of so far unexplored fundamental electronic properties of TMDs, and the first implementation of a practical interface between TMD-based emitters and basic photonic structures. We will perform a systematic investigation of the optical properties of monolayer-thick domes formed after H irradiation and extend this by controllably applying strain via piezoelectric actuators to H-inflated domes. We will investigate the influence of the strain also on interlayer excitons formed across van der Waals heterostructures. We will achieve control of the emission intensity of the interlayer exciton in domes formed in heterobilayers, because the interlayer distance can be varied acting on the temperature, due to the condensation of H2 trapped into the dome. Finally, it is possible to selectively expose prescribed regions of a sample to H irradiation by defining openings in H-opaque masks. We will take advantage of this approach by making use of electron-beam lithography to fabricate nanometer-sized domes, which we will then exploit as site-controlled emitters and for coupling into waveguides and photonic crystal cavities.
Fields of science
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Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
00185 Roma
Italy