Observation of excitons at room temperature in ZnSxSe1-x nanostructures embedded in a porous Al2O3 template

Abstract

This work presents the phenomenon of dielectric confinement of the excitons of quasi-zero-dimensional nanostructures of a ZnSxSe1-x solid solution in a dielectric template of porous anodic aluminum oxide (AАО), which are synthesized by a simple method of vacuum thermal evaporation. The structures obtained possess stable excitons at room temperature with exciton binding energies ranging from 90 to 250 meV depending on composition and size of semiconductor nanostructures. The phenomenon of dielectric confinement of excitons is directly demonstrated by varying the dielectric constant of the semiconductor material. The quantum confinement in the structures under study is small since the dimensions of the nanoparticles exceed considerably the Bohr radius of exciton. The increase in exciton binding energy with decreasing dimensions of nanoparticles is discussed. This increase can be explained by an increase in the dielectric surroundings.