In recent years

a successful effort has been made to grown Ⅱ-Ⅵ compound semiconductor because of their potential applications in visible light emitting devices in blue green region. ZnSe

1-

x

Te

x

with a range of

x

value

can be either n-type or p-type

was selected as quantum well material. We prepared a (ZnCdTe

ZnSeTe)/ZnTe complex quantum wells structure grown by LP MOCVD on GaAs (100) substrate. The photoluminescence (PL) spectra showed that there were two emission peaks at 2.201 and 2.128eV(labeled

I

1

and

I

2

respectively)

which was assigned to the emission of Zn

0.9

Cd

0.1

Te and ZnSe

0.2

Te

0.8

well layer

respectively. With the increasing of the excitation intensity

the PL intensity ratio of

I

2

/

I

1

grew significantly firstly

and then decreased slightly. This phenomenon was interpreted in terms of the formation of the build in electric field caused by the different tunneling rates of electrons and holes through the barrier in the structure.