Engineering the excitonic and photonic properties of atomically thin semiconductors

Abstract

Atomically thin and layered semiconductors are of broad interest to the physics and engineering communities in the past decade. As true members of the mesoscale, such materials have exotic and potentially advantageous properties not found in bulk semiconductors. Using materials like the transition metal dichalcogenides or hexagonal boron nitride for novel optoelectronic and nanophotonic devices requires (i) a fundamental understanding of the optical properties of their excitons and (ii) techniques for engineering the emission of light by excitons. This thesis addresses both points and demonstrates how the radiative properties of excitons in various van der Waals materials can be controlled by photonic environment engineering. Several examples of this engineering include: steering the reflection of a laser off a MoSe2 monolayer by spatially modulating the charge profile in the monolayer; electromechanically modifying the radiative decay rate of excitons by their proximity to a mirror; efficiently extracting dark excitons from a nanoscale strain landscape by tapered optical fibers; and Purcell enhancing exciton emission in boron nitride nanophotonic cavities.