Two-Electron Satellites in PL

Another characteristic of the neutral donor-bound exciton transition is the TES transition in the spectral region of 3.32-3.34 eV. These transitions involve radiative recombination of an exciton bound to a neutral donor, leaving the donor in the excited state (2s, 2p states), thereby leading to a transition energy that is less than the DBE energy by an amount equal to the energy difference between the first excited (2s, 2p) 

Meyer et al. [75] studied the TES spectral range of different bulk ZnO samples in detail to obtain the binding energies of various donors. They have observed the splitting of TES lines into 2s and 2p states as a result of the effects of anisotropy and the polar interaction with optical phonons in polar hexagonal semiconductors. The effects of anisotropy and the polaron interactions were combined by employing the second-order perturbation theory and the results of numerical calculations of the 

PL line Chemical identity [75] Energy (eV) (Donor binding energy, meV)  

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