Light Emission of 2D Interlayer Moiré Excitons

Recently, 2D twisted bilayers with interlayer lattice mismatch and/or rotational misalignment have emerged as a powerful platform for studying unconventional properties such as the interlayer exciton (IX), where electrons and holes located in different monolayers couple to form a bound state. The IXs can further be spatially concentrated into periodic potential minima modulated via the moiré landscape, forming uniform periodic quantum-dot-like emitter array. In this talk, I will introduce optical characterization of 2D heterobilayer transition metal dichalcogenides (TMDCs) interlayer excitons under different configurations of interlayer twisting angles and material selections. 2D heterobilayers with deterministic interlayer twist angle were prepared using a custom-built layer stacking system. Here, we studied the light emission properties with time-resolved photoluminescence (PL), temperature-dependent PL, and magneto-PL. Through the PL studies, we were able to extract key parameters of interlayer excitons such as lifetime, binding energy, valley polarization, etc. These results represent an advance in the understanding of the physics of 2D interlayer excitations and the future implementation of these TMDC materials within tunable light-emitting devices.