Imaging and controlling localized interlayer excitons in 2D semiconductor heterostructures

The properties of excitons in 2D semiconductors are strongly modifies by their spatial localization. One effect is significant reduction in the rate of radiative decay radiative decay  and an associated decrease in linewidth.  In addition, localization allows us to create individual quantum systems, which are analogous to trapped atoms.  Localization permits control of the exciton center of mass motion, creates strong optical nonlinearities through enhanced exciton-exciton interactions, and can produce quantum emission for sufficiently strong confinement. 

 

In this presentation, we describe recent progress towards creating localized excitons and excitons arrays with both spatial and spectral control. Two engineered approaches to exciton localization will be presented. The first is  strain control on the nanometer length scale through substrate patterning.  The second is exciton localization through electric-field control using both in-plane fields for intralayer excitons in monolayers and out-of-plane fields for interlayer excitons in heterostructures.  The possibilities of creating coupled arrays of such localized excitons will be discussed.