Résumé
An optical spectroscopy study of unintentionally doped CdTe/Cd
0.88Mn
0.12Te double quantum wells (QWs) revealed formation of a negatively charged exciton state in the thicker QW due to the interwell tunneling of photoexcited electrons. A suggested model based on the chemical equilibrium requirement has explained the behavior of the X
−-intensity in the photoluminescence spectra with excitation energy and excitation density variation. In-plane concentration of X
− states at constant excitation has been estimated to be limited by 6×10
10
cm
−2. X
− binding energy is found to be 3.7
meV.