Thermal quenching of bound exciton emission due to phonon-induced non-radiative transitions: experimental data for CdTe and InP

Abstract

The thermal quenching of (A0X) and (D0X) emission lines due to processes of the type (A0X) to A0+X and (D0X) to D0+X, respectively, is discussed in terms of nonradiative phonon-induced transitions. The onset and the strength of the quenching are determined by the exciton-impurity binding energy as well as the amount of lattice relaxation accompanying these transitions. The latter effect, which has obviously been overlooked in earlier discussions, depends upon the degree of localization of the 'persistent' particle (hole or electron, respectively) and is relatively strong in the case of the 'deep' acceptors (such as CuCd and AgCd in CdTe). The quantitative correlation of the quenching parameters (and also of the capture coefficients related to the inverse processes) with the ionization energies of A0 and D0, which is expected on this basis, is confirmed by experimental results for CdTe and InP.