Stimulated emissions in Zn1-xCdxSe/ZnSe multi-quantum well (MQW) struc
tures have been studied under high optical excitation in the temperatu
re range 4.2-300 K. With increasing the excitation intensity, the stim
ulated emission at low temperatures shows a red shift of the peak ener
gy and a quadratic dependence of the intensity on the excitation inten
sity. The observed stimulated emission process is interpreted by excit
on-exciton scattering in the MQWs. At room temperature, highly excited
MQWs show a markedly broadened emission, the intensity of which is in
proportion to the excitation intensity. We attribute the emission pro
cess to electron-hole plasma (EHP) recombination. The observed emissio
n spectra are in good agreement with calculations by using models of e
xciton-exciton scattering and EHP recombination. The stimulated emissi
on mechanisms elucidated in the present study are closely related to t
hose tailing place in ZnSe-based blue laser diodes.