Chun Hung Lui

Abstract A tunable interface between flying photons and stationary quantum states is important for quantum networks. Quantum-confined charged excitons are attractive in this context because they combine single-photon emission with localized charge states. However, realizing nanoscale electrostatic confinement that is reversible, robust and spectroscopically resolvable remains challenging.

Abstract Semiconductor heterojunctions are ubiquitous components of modern electronics. Their properties depend crucially on the band alignment at the interface, which may exhibit straddling gap (type-I), staggered gap (type-II) or broken gap (type-III). The distinct characteristics and applications associated with each alignment make it highly desirable to switch between them within a single material.

Heat treatment can transform some moiré superlattices into fully commensurate bilayers, where atoms in opposite layers align perfectly with each other. This structural transformation gives rise to markedly brighter interlayer excitons. Monolayer transition metal dichalcogenides (TMDs), such as MoS2, MoSe2 and WSe2, constitute an outstanding family of two-dimensional (2D) semiconductors with remarkable electronic and optical properties.