The decay process of photo-generated electrons and shallow-trapped electrons was measured by microwave absorption method while a series of powder material (ZnCd)S:Cu and ZnS:Mn

Cu were excited by ultra-short pulse laser. It is measured that the lifetime of photoelectrons is 1 864ns and that of shallow-trapped electrons is 2 144ns in the material (Zn

0.97

Cd

0.03

)S:Cu. The lifetime of photoelectrons is 1 376ns and that of shallow-trapped electrons is 1 888ns in the material (Zn

0.83

Cd

0.17

)S:Cu respectively after increasing the concentration of Cd

2+

ion. The lifetime of photoelectrons in conduction band only have a decrease of 488ns

thereby it is believed that the concentration of Cd

2+

ion has less influence on the lifetime of electron in conduction band. At the same time

it is measured that the peak position of luminescent spectrum shifts toward long-wave band along with Cd

2+

concentration enhancing. The material ZnS:Cu undoped with Cd

2+

ion shows a luminescent spectrum peaked at 505nm and the luminescent spectrum peaked at 565nm for (Zn

0.83

Cd

0.17

)S:Cu doped with Cd

2+

concentration at 17%. The shifting range toward long-wave band is 60nm. These said the phenomena are likely resulted from the change of bandgap width of luminescent material due to the present of CdS in the host. The decline of luminance output to some extent is simultaneously noticed with the increase of Cd

2+

concentration.For the material ZnS:Mn

Cu

it is discovered that the lifetime of photoelectrons decreased to a large extent from 1 720ns to 432ns accompanied with an increase of brightness during the course of enhancing the content of Cu from 0.02 to 0.5%.The maximum luminance was obtained at Cu content of 0.1% and subsequently the brightness declined with the enhancing content of Cu. Therefore

it is considered that a mass of non-radiative transition which can not make for the luminescence is likely to occur so that it can result in diminished brightness at excessively higher content of Cu. Accordingly

there exists a optimal value of the content of Cu for the luminescent material ZnS:Mn

Cu.