Exciton-related luminescence of ZnO and its optoelectronic applications

Excitons, as core elementary excitations in semiconductors, encompass fundamental scientific issues of longstanding interest in condensed matter physics and optoelectronics, including their formation, classification, dynamic behaviors, and radiative recombination mechanisms. This review focuses on excitons of zinc oxide (ZnO), a prototypical wide-bandgap semiconductor, highlighting its large exciton binding energy of \sim 60 meV, its distinctive luminescence spectral structure, and the intrinsic physical origins that enable stable excitonic emission at room temperature. In the ZnO system, its exceptionally high exciton binding energy stems from weak dielectric screening and strong Coulomb interaction, endowing it with irreplaceable advantages for room-temperature ultraviolet optoelectronic devices. Besides, the exciton lasing in different ZnO micro/nano structures is introduced, as well as the applications such as the laser sensing and the ultraviolet light emitting devices. Moreover, the interactions of ZnO excitons with excitons, photons, phonons, and plasmons are mentioned and discussed. This review summarizes the exciton-related luminescence properties of ZnO, a material with great potential for functional optoelectronic applications.