Coherence properties of interlayer exciton electroluminescence in atomically thin semiconductor heterostructures*

Atomically thin semiconductor heterostructures based on transition metal dichalcogenides offer an electrically tunable platform for developing coherent on-chip optoelectronic devices. Interlayer excitons in these systems form out-of-plane dipoles and exhibit long lifetimes owing to the spatial separation of electrons and holes. The bosonic nature of excitons and strong dipolar interactions make them ideal candidates to search for Bose-Einstein condensation in 2D materials. Here, we study the optoelectronic properties of MoSe₂/hBN/WSe₂ devices and compare their emission profile to that of non-hBN spaced samples. In the former system, we observe a threshold in the electroluminescence of interlayer excitons as we increase the applied forward bias. We further characterize the nature of this transition by performing measurements of the second-order correlation function. Lastly, we discuss how first-order correlation measurements can reveal the coherence properties of the interlayer excitons.