An exciton is a bound state of an electron and an electron hole in a solid, typically a semiconductor or an insulator. It’s a quasiparticle resulting from the interaction between an excited electron and the hole it leaves behind in its original energy state. When an electron absorbs energy, it moves to a higher energy level, leaving an empty space, or hole, in its previous position.
This excited state forms an exciton when the electron and the hole are attracted to each other due to their opposite charges. They orbit each other, behaving somewhat like a “composite particle” with its own distinct energy, momentum, and spin. Excitons can exist in different states, such as bound or unbound, depending on factors like temperature and material properties.
Excitons play a crucial role in understanding the optical and electronic properties of various materials. They are involved in processes like light absorption, emission, and energy transfer, contributing significantly to the behavior of semiconductors and impacting technologies like solar cells, LEDs, and photodetectors.
