Phenomenological modeling of exciton transport in two-dimensional transition metal dichalcogenides

Excitons dominate the optoelectronic response of two-dimensional (2D) transition metal dichalcogenides (TMDs) because dimensional confinement, dielectric screening, and direct band gaps leads to large exciton binding energies, even at room temperatures. As a result, semiconducting TMDs offers a unique platform for studying exciton dynamics and transport in 2D systems. Classical diffusion-drift models have been commonly used to model exciton transport resulting from varying exciton concentrations and strain engineering. Similarly, rate equations written from level diagrams are commonly used to study exciton dynamics, such as population recombination dynamics, coherent dynamics, and valley polarization dynamics. In this presentation, the aforementioned approaches are combined and the applicability of each model is discussed. In addition, application of the model to strained, junctioned, alloyed systems is discussed. Understanding and optimizing exciton transport and dynamics in 2D TMDs will allow for the creation and optimization of novel devices.