Many authors have investigated the self-activated center(SA) in ZnSe crystals

[1-4]

. It is known that the chemical structure of the SA center ascribes to a F

Zn

-D complex

here VZn is a Zn vacancy and D is a donor

and the acceptor related to the SA center is located at 0.65-0.75eV

[5

6]

or at 0.5~0.6eV

[7]

above the valance band. In this paper a deep acceptor level of Ev+0.65eV related to the SA center is determined for the first time by ODLTS technique

[8-11]

. Nominally undoped ZnSe crystals used in this study were grown by sublimation in our laboratory

[12-13]

. Dice of ZnSe were annealed in molten Zn-Ga alloy with different concentration of Ga at 900℃ for about 100h. ZnSe.Ga MS diodes were prepared by making In ohmic contact on one face of a die and evaporating Au potential barrier electrode on to the opposite face.