A study of luminescence thermal quenching in ZnCdSe/ZnSSe quantum wells for the optimal design of blue laser structures

We investigate the thermal behaviour of the emission of Zn_1-xCd_xSe/ZnS_ySe_1-y quantum wells (QWs) grown on GaAs and ZnSe substrates using excitation-intensity-dependent photoluminescence (PL) over the range 5-300 K. The onset of carrier leakage out of the QWs is shown to be governed not only by the barrier height of the well but also by the density of extended defects in the vicinity of the well. From analysis of the Arrhenius plots via a simple model, we provide a semi-empirical law valid in the high injection regime, in which the only adjustable parameter is the confinement energy of the QW. From this model the minimum confinement energy to avoid carrier leakage in the active area of light emitters is determined to be 11k_BT. © 1998 Elsevier Science B.V. All rights reserved.