Excitons are optically generated quasi-particles in solids which are composed of electron-hole pairs bounded by Coulomb interactions. Excitonic devices are potentially well suited to the development of a promising alternative to electronics with lower energy, efficient photon transformation and photonic coupling.

By staking two transition metal chalcogenides (TMDCs) monolayers on top of each other, the heterostructure with a type-II band alignment enables the formation of long-lived interlayer excitons (IXs). This gives rise to a sizable permanent out-of-plane electrical dipole moment, which makes IXs a promising platform to realize electrically controlled excitonic devices.

In the research seminar, Dr. Sun will show by applying local electric fields on IXs, one can realize valley-polarized excitonic transistors with switching action, confinement and control over diffusion length in a reconfigurable potential landscape. What’s more, by using spatially and temporally resolved photoluminescence imaging, one could make a movie for the motion of IXs and observe the effect of repulsive dipole-dipole interactions on their dynamics. The dipolar interactions combined with the electrical control of interlayer excitons opens up appealing new perspectives for excitonic devices.