Optoelectronic integrated circuits and photonic integrated circuits on silicon substrate will meet the needs of information transmission and processing in the future. ZnSe are semiconductor materials with wide direct bandgap (2.7eV) at room temperature and have a high potential for realizing blue light emitting devices for optoelectronic/integrated optics applications as well as fundamental studies.High quality ZnSe epilayers on Si(111) substrate were obtained at 300℃ by LP-MOCVD

in which hydrogen selenium(H

2

Se) and dimethylzinc (DMZn) were used as the reactants. The pretreatment of the Si substrates was divided into two parts. The first part was a degreasing process

the second step is the etching procedure. ZnSe epilayer characteristics were investigated by X-ray diffraction

scanning electron microscope energy dispersive spectrometer (SEMEDS) and photoluminescence (PL). A single intense diffraction line of the ZnSe crystal was observed

confirming that the epitaxial layer was a (111)-oriented single crystalline layer. The EDS analysis on a SEM of the ZnSe epilayer on Si showed that there were only three elements including zinc

selenium and silicon. This indicated there is no significant impurities in the epilayer. In addition

the atomic ratio of Zn/Se was close to 1

the ZnSe epilayers had good stoichiometry. For the growth at 300℃ with H

2

Se flow rate fixed as 20mL/min

and a total H

2

flow of 3OOOmL/min under a reaction pressure of 10.1×10

3

Pa

the growth rates were determined by variation of DMZn flow rate. The growth rate increased significantly with the DMZn flow rate increasing from 3mL/min to 10mL/min. While the DMZn flow rate was fixed at 5mL/min

the H

2

Se flow rate incressed from 5mL/min to 20mL/ min

the grow rate had no significantly change. The results indicated that DMZn flow rate predominately controled the growth rate of ZnSe epilayer in this work.A strong blue near band gap photoluminescence(PL) peak around 447nm was observed at 77K without any additional PL signal at longer wavelengths. This indicates the absence of deep trapping centers. This peak shifts to around 465nm at room temperature

reflecting the decrease of the band gap with increasing the temperature. The presence of this intrinsic near band gap emission line in the PL spectrum even at room temperature is a further indication for the high quality of the ZnSe epitaxial layer. On the basis of the observed ZnSe/Si epitaxial film properties

the material has potential for optoelectronic integrated circuits and photonic integrated circuits.