Effects of strong electron–hole exchange and exciton–phonon interactions on the exciton binding energy of aluminum nitride

Abstract

In this study, the exciton binding energies of AlN are calculated by the anisotropic effective mass theory, which considers the strong electron–hole exchange and Fröhlich-type exciton–phonon interactions. Our calculated results are in good agreement with recent experimental results, indicating that the electron–hole exchange and exciton–phonon interactions play essential roles in describing the excitonic structure of AlN. We estimate that the exciton binding energies of AlN are 53.7 and 67.3 meV, for the spin-singlet and the spin-triplet states, respectively. In addition, a universal correlation has been found in compound semiconductors including AlN, where the effect of the electron–hole exchange and Fröhlich-type exciton–phonon interactions almost compensates each other on the binding energy of a spin-singlet exciton.