Negatively charged exciton formation in an asymmetric double CdTe/(Cd,Mn)Te QWs

摘要

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 X 10~10 cm~-2. X~- binding energy is found to be 3.7 meV. direct c 1999 Elsevier Science B.V. All rights reserved.