Around x-ray, notice strange energy concentration

Wiktionary Word definitions in Wiktionary
n. (context physics English) A bound state of an electron and an electron hole in an insulator or semiconductor

Wikipedia Word definitions in Wikipedia
An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force . It is an electrically neutral quasiparticle that exists in insulators , semiconductors and in some liquids. The exciton ...