Effect of ion induced damage on carrier lifetimes in strained CdZnSe/ZnSe quantum wells

Studies of the effects of reactive ion etching on molecular beam epitaxy gr own CdxZn1-xSe/ZnSe strained quantum wells (QWs) using photoluminescence (P L) and time-resolved reflectivity measurements are reported. The shallow (5 0 nm cap layer) QW samples exhibit a blueshift in their PL peak position as a function of etch voltage up to a certain point, after which the blueshif t is reduced. The reduction in the blueshift of the PL spectrum is strongly correlated with a reduction in the carrier lifetimes measured by transient reflectivity. From these experiments we suggest that the initial blueshift is a result of ion damage at the surface interacting with strain in the QW . On the other hand, the reduced carrier lifetime at higher voltages is a r esult of more severe structural damage in the QW. (C) 2000 American Institu te of Physics. [S0021-8979(00)00706-4].