Excitons in 2D materials
The band structure in a semiconductor features a top valence band and the lowest conduction band.
The energy difference between these bands is the bandgap.
When shining light with energy larger than the bandgap, the electrons in the valence band are pumped up to the conduction band and leave holes in the valence band.
Electrons like to meet up with holes and form excitons!
In two-dimensional (2D) semiconductors, the electron is attracted by the hole stronger.
In other words, the exciton in 2D materials binds tighter than in 3D materials.
As a result, it can interact with light more actively.
The characteristic of the exciton is determined by the properties of the electron and the hole.
Electrons and holes can come from various sources and thus behave differently.
In some materials, the exciton is bright. While in some materials, the exciton is likely to be dark.
In artificial 2D materials, the brightness of the excitons is tunable.
We are interested in studying ...
how the excitons form
how to manipulate the excitons
how the excitons interact with other entities
(many-body physics)how to use exciton in the daily life applications that are already being used
invent new device using the unique properties of exciton BEC