Interfacially Bound Exciton State in a Hybrid Structure of Monolayer WS₂ and InGaN Quantum Dots.

Abstract

van der Waals heterostructures that are usually formed using atomically thin transition-metal dichalcogenides (TMDCs) with a direct band gap in the near-infrared to the visible range are promising candidates for low-dimension optoelectronic applications. The interlayer interaction or coupling between two-dimensional (2D) layer and the substrate or between adjacent 2D layers plays an important role in modifying the properties of the individual 2D material or device performances through Coulomb interaction or forming interlayer excitons. Here, we report the realization of quasi-zero-dimensional (0D) photon emission of WS₂ in a coupled hybrid structure of monolayer WS₂ and InGaN quantum dots (QDs). An interfacially bound exciton, i.e., the coupling between the excitons in WS₂ and the electrons in QDs, has been identified. The emission of this interfacially bound exciton inherits the 0D confinement of QDs as well as the spin-valley physics of excitons in monolayer WS₂. The effective coupling between 2D materials and conventional semiconductors observed in this work provides an effective way to realize the 0D emission of 2D materials and opens the potential of compact on-chip integration of valleytronics and conventional electronics and optoelectronics.