Descrizione del progetto
Cupole minuscole con nuove proprietà ottiche aprono le porte a dispositivi optoelettronici innovativi
I monostrati di dicalcogenide di metallo di transizione sono una classe di nanolamine 2D atomicamente sottili costituite da un metallo di transizione e un calcogeno. Sono di estremo interesse per numerose applicazioni a causa delle loro proprietà optoelettroniche uniche. Tuttavia, per sfruttare questi materiali in applicazioni commerciali, abbiamo bisogno di processi di fabbricazione riproducibili ed economici per la produzione su larga scala. Il progetto SELENe, finanziato dall’UE, affronterà questa importante strozzatura producendo cupole spesse a un solo strato a partire da campioni multistrato tramite l’irradiazione di idrogeno. Queste minuscole cupole esotiche saranno quindi caratterizzate per le loro proprietà ottiche ancora sconosciute e per la potenziale applicazione in strutture optoelettroniche ad alta tecnologia.
Obiettivo
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.
Campo scientifico
Parole chiave
Programma(i)
Argomento(i)
Meccanismo di finanziamento
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinatore
00185 Roma
Italia