ZnSe is a direct-gap Semiconductor with the zinc-blende crystal structure and a relatively large band-gap energy of 2.7eV at 300K. Excitons in ZnSe are strongly bound with a binding energy of ~20meV. Recently

attention has been paid to the strained layer quantum well using a ZnSe layer as the well material

which provides the possibility to obtain excitonic emission and optical bistability (OB).The growth of ZnSe-ZnS MQWs with steep interface and narrow well have an important significance for studying quantum size effect

subband transition and carrier scattering. Taike et al.

[2]

has reported the growth of ZnSe-ZnS SLS with well thickness (

L

w

) of ~0.5nm by MBE. But the PL peak position is about 430nm which is not agreed with the result calculated by Kroning-Penney model. In this paper

we report

for the first time

the preparation of narrow well ZnSe-ZnS MQWs with well Thickness(

L

w

) of ~0.5nm and the excitonic peak blue shift to 375nm (3.304eV). X-ray diffraction shows the ZnSe-ZnS with good quality periodic structure. The excitonic peak in PL spectrum shifts towards higher energy side as the well thickness reducing

indicating the quantum size effect of the ZnSe-ZnS MQWs.