Description du projet
De minuscules dômes aux propriétés optiques inédites ouvrent la voie à des dispositifs optoélectroniques innovants
Les monocouches de dichalcogénure de métaux de transition sont une classe de nano-feuilles 2D atomiquement fines composées d’un métal de transition et d’un chalcogène. Elles présentent un intérêt extrême pour de nombreuses applications en raison de leurs propriétés optoélectroniques uniques. Cependant, pour pouvoir exploiter ces matériaux dans des applications commerciales, nous avons besoin de voies de fabrication reproductibles et rentables pour une production à grande échelle. Le projet SELENe, financé par l’UE, s’attaquera à cet important goulet d’étranglement en produisant des dômes d’une seule couche d’épaisseur à partir d’échantillons multicouches par irradiation à l’hydrogène. Ces minuscules dômes exotiques seront ensuite caractérisés pour leurs propriétés optiques encore inconnues et leur application potentielle dans des structures optoélectroniques de haute technologie.
Objectif
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.
Mots‑clés
Programme(s)
Régime de financement
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinateur
00185 Roma
Italie