There has been considerable interest in blue electroluminescence (EL) in ZnSe diodes recently

[1-3]

. In our earlier work

the attention was directed to the determination of the origin of the blue emission spectrum at room tem-peratature

[4

5]

and the improvement of the spatial distribution of blue EL in ZnSe MIS diodes

[6]

.The study of the blue EL in ZnSe focused on bulk crystals by sublimation and other methods at high temperature.The as-grown ZnSe crystals usually contained a large number of intrinsic defects

and had high resistivity even if donor impurities had been dopped.So far

many papers reported on thin epitaxial films of ZnSe grown by MOCVD

[7

8]

MBE

[9

10]

LPE

[11

12]

and VPE

[13-16]

and high quality ZnSe epilayers were grown.However there were a few reports[17

18] on preparing blue EL in ZnSe MIS diodes using the ZnSe epilayers. In the present paper we first reported the blue EL at room temperature from the vapor phase epitaxial ZnSe grown on GaAs.