Screening Effects in the Exciton‐Electron Luminescence Spectra

Abstract

The exciton-electron interaction process in the luminescence spectra which i s important at high concentrations of free carriers was introduced by Benoit B la Guillaume et al. (1). Later the problem was repeatedly discussed in theoretical (2), (3) and experimental (4) works.In the luminescence spectra the exciton-electron interaction displays a wide band whose intensity is proportional to the concentration of the free c a r r i e r s n.In this paper it is shown that the screening effects disturb the linear concentration dependence of the luminescence band intensity. In the region of high concentrations the intensity falls with increasing n. At n = n it reaches its maximum. Further growth of the concentration leads to a sharp decrease of the intensity and to a turning-off of the exciton-electron recombination process.

Cathodoluminescence on the diffusion front of CdS doped with trivalent metals

“…Henry and Nassau (1970) have determined very high oscillator strengths for bound excitons in very lightly doped crystals, from lifetime measurements. Skaistys and Valkunas (1976) have recently proposed a mechanism which gives an exciton line luminescence intensity which increases rapidly with increasing free electron concentration up to a critical value and decreases again above this value. The exciton line emission at the diffusion front can thus be regarded as consistent with published data.…”