ZnS:Cu

Nd

Cl thin films have been shown to give good DCEL with spectrum characteristic of trivalent neodymium ions. Nd

3+

ions form stable luminescence centers and can directly convert electrical energy into optical energy with efficiency of~10

-4

W/W.The thin films have two parallel electrodes consisting of a semi-transparent mirror formed by the conducting SnO

2

on the glass and a completely reflecting gold back electrode. These parallel electrodes form an ideal cavity for producing the oscillations of a given wavelength emission.More attentions are paied to the transitions from excited state

4

F

3/2

to ground state

4

I

9/2

with production of the emission at ~900nm and to state

4

I

11/2

with production of the emission at ~1080nm. In these two spectral groups

some sharp spectral lines increase more quickly with applied voltage than the common spectral lines. These results are attributed to a tendency of population inversion involving the excited state

4

F

3/2

and sub-levels of the ground states

4

I

9/2

and

4

I

11/2

and then to an occurrence of stimulated emission in the suitable harmonic oscillation cavity formed by two parallel electrodes.The experimental results reported here show the possibility of fabricating a thin film laser device in II-VI compounds doped with rare earth ions.