In the scope of the project, the main objectives of the individual work packages (WPs) have been achieved and additional unexpected results have been established. In WP I with focus on moiré interference effects, chemical vapor deposition (CVD) synthesis of laterally extended two-dimensional semiconductors in the form of monolayer, bilayer and heterobilayer TMD crystals has been established and protocols have been developed to fabricate van der Waals heterostructures and devices via exfoliation and dry-transfer methods. High quality of monolayers and van der Waals heterostructures embedded in hexagonal boron nitride have been fabricated, as confirmed by complementary analysis techniques and employed in various experimental settings. The main results of WP II with focus on exciton circuitry have been addressed in experiment and theory, and substantial progress has been achieved in the understanding of light-matter interactions mediated by excitons in layered TMD semiconductors. In particular, magneto-optical signatures of excitons in different spin, valley, material and layer configurations observed experimentally on representative TMD monolayers, homobilayers and heterostructures have been substantiated by theoretical modeling of exciton Landé factors from first-principles. Moreover, theoretical understanding of atomic lattice reconstruction on mesoscopic length scales in near-commensurate small-twist heterostructures has been developed. For heterostructures of non-commensurate layers with canonical moiré interference effects, experimental evidence and theoretical modeling have been developed to explain the complexity of optical phenomena on the basis of combined effects of moiré potential and interlayer hybridization. Most remarkably, moiré heterostructures have been identified to support a plethora of correlated many-body phenomena of excitons, charges and spins ordered on triangular moiré lattices. Finally, in WP III with focus on hybrid TMD-cavity systems, formation of exciton-polaritons in the regime of strong coupling has been realized for TMD monolayers at room and cryogenic temperatures with open micro-cavities and nanoplasmonic elements. Moreover, using cryogenic open-cavities, Purcell enhancement in the photoluminescence has been demonstrated for interlayer excitons in TMD heterobilayers, and the strong-coupling regime has been established for moiré excitons subject to voltage-controlled doping. For electron-charged moiré exciton-polaritons signatures of correlation-induced magnetism have been demonstrated. The successful achievements of individual and interrelated milestones of all three WPs, as disseminated in scientific publications as well as at national and international conferences and workshops, represent cumulatively the overall success of the project towards developments of novel quantum optical and opto-valleytronic elements based on layered TMD semiconductors and heterostructures.
