Exciton-binding energy

Figure Al.3.25. Schematic illustration of exciton binding energies in an insulator or semiconductor.

Even in semiconductors, where it might appear that the exciton binding energies would be of interest only for low temperaPire regimes, excitonic effects can strongly alter tlie line shape of excitations away from the band gap. 

Mathieu H, Lefebvre P, Christol P (1992) Simple analytical method for calculating exciton binding-energies in semiconductor quantum-wells. Phys Rev B 46 4092... 

Here, a brief summary is provided of the current understanding of the electronic structure properties of the hetero junction interface. We start with the basic picture of the energetics (Sec. 2.1), based on the offset between the frontier orbitals of the two polymer species this offset triggers the dissociation of the photogenerated exciton if the exciton binding energy cb 0.5 eV can be overcome. To refine this picture, explicit electronic structure calculations are necessary, which pose a formidable challenge for the interfacial systems under consideration. Secs. 2.2 and 2.3 summarize recent efforts in this direction [41,43,44,56]. 

Table 3.1. Band-gap energy Eg and the (ground state) exciton binding energy Elh of ZnO, GaN, MgO, and CdO...

Table 7.6. Comparison of band gap energies Es, exciton binding energies Exb, and 1LO and 2LO phonon energies hwilo and Ri lo, calculated from the PL peak energies of a ZnO single crystal (Eagle Picher) and a PLD ZnO thin film on a-plane sapphire at 2 K, as given in Fig. 7.20 [63]...

One can say that the obtained by us experimental results upon 2D exciton localization (taking place due to the growth of the crystal dielectric permeability anisotropy parameter) with o are very close to [27] where the behaviour of polaron excitons in parabolic quantum dots were considered and shown that the dot size decrease results in increasing the exciton binding energy. 

TABLE 2 Summary of free exciton binding energies in GaN. PLE, PL, PR, R, TPS mean photoluminescence excitation spectroscopy, photoluminescence, photoreflectance, reflectance and two-photon spectroscopy respectively. 

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