Engineering the electronic band structure of transition metal dichalcogenide heterostructures in device geometries

• Applicant: Professor Dr. Alexander Grüneis, since 8/2022
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 470082990

The recent years have witnessed the advent of precise control of two dimensional (2D) matter via the stacking in van der Waals heterostructures. Heterobilayers of semiconducting 2D materials – transition metal dichalcogenides (TMDs) – attain new electronic and optical properties, such as interlayer excitons in type-II heterostructures. These interlayer excitons can be manipulated electrically by tuning the electronic energy bands in devices, which opens up the perspective of using TMD heterostructures for device applications. Nevertheless, the relationship between the electronic band structure and the optical properties has yet to be revealed. This project aims to address this challenge by using a unique combination of in operando studies with spatially-resolved angle-resolved photoemission spectroscopy (SR ARPES) and ultra-high vacuum photoluminescence (UHV PL) spectroscopy. Such a unified approach will allow to tune charge carrier concentration and introduce the junction field effect in TMD-heterostructure-based devices directly during measurements. SR ARPES and UHV PL experiments will be performed on the same samples in ultra-clean conditions without unintended functionalization. The results obtained will provide new insights into the engineering of the electronic band structure and exciton physics in TMDs heterostructures, and will pave the way for the implementation of these materials in novel optoelectronic devices. The project will also contribute to the development of in operando studies of a wide range of 2D materials and their heterostructures.

• DFG Programme: Research Grants
• International Connection: Austria
• Ehemaliger Antragsteller: Dr. Boris Senkovskiy, until 7/2022