Thermal effect on quantum confinement in ZnS0.06Se0.94/Zn0.8Cd0.2Se quantum wells

ZnS0.06Se0.94/Zn0.8Cd0.2Se quantum wells (QW) were studied by temperature-dependent photoluminescence (PL) measurement. We observed two PL peaks due to the band-to-band transition in ZnS0.06Se0.94 barrier, Eg(0)=2.819 eV, and the transition of heavy hole to first conduction subband in Zn0.8Cd0.2Se well, Ehh1(0)=2.545 eV. The relative thermal coefficients of these two constituent materials are quite different, resulting in a temperature-dependent quantum confinement. The reduction of the quantum confinement at high temperatures induces a leakage of carrier and leads to a quenching of the PL intensity. The activation energy for the PL quench is about 188.4 meV.